June 2, 2016
The first domesticated animals may have been tamed twice.
Tens of thousands of years ago, before the internet, before the Industrial Revolution, before literature and mathematics, bronze and iron, before the advent of agriculture, early humans formed an unlikely partnership with another animal—the grey wolf. The fates of our two species became braided together. The wolves changed in body and temperament. Their skulls, teeth, and paws shrank. Their ears flopped. They gained a docile disposition, becoming both less frightening and less fearful. They learned to read the complex expressions that ripple across human faces. They turned into dogs.
Today, dogs are such familiar parts of our lives—our reputed best friends and subject of many a meme—that it’s easy to take them, and what they represent, for granted. Dogs were the first domesticated animals, and their barks heralded the Anthropocene. We raised puppies well before we raised kittens or chickens; before we herded cows, goats, pigs, and sheep; before we planted rice, wheat, barley, and corn; before we remade the world.
“Remove domestication from the human species, and there’s probably a couple of million of us on the planet, max,” says archaeologist and geneticist Greger Larson. “Instead, what do we have? Seven billion people, climate change, travel, innovation and everything. Domestication has influenced the entire earth. And dogs were the first.” For most of human history, “we’re not dissimilar to any other wild primate. We’re manipulating our environments, but not on a scale bigger than, say, a herd of African elephants. And then, we go into partnership with this group of wolves. They altered our relationship with the natural world.”
Larson wants to pin down their origins. He wants to know when, where, and how they were domesticated from wolves. But after decades of dogged effort, he and his fellow scientists are still arguing about the answers. They agree that all dogs, from low-slung corgis to towering mastiffs, are the tame descendants of wild ancestral wolves. But everything else is up for grabs.
Some say wolves were domesticated around 10,000 years ago, while others say 30,000. Some claim it happened in Europe, others in the Middle East, or East Asia. Some think early human hunter-gatherers actively tamed and bred wolves. Others say wolves domesticated themselves, by scavenging the carcasses left by human hunters, or loitering around campfires, growing tamer with each generation until they became permanent companions.
Dogs were domesticated so long ago, and have cross-bred so often with wolves and each other, that their genes are like “a completely homogenous bowl of soup,” Larson tells me, in his office at the University of Oxford. “Somebody goes: what ingredients were added, in what proportion and in what order, to make that soup?” He shrugs his shoulders. “The patterns we see could have been created by 17 different narrative scenarios, and we have no way of discriminating between them.”
The only way of doing so is to look into the past. Larson, who is fast-talking, eminently likable, and grounded in both archaeology and genetics, has been gathering fossils and collaborators in an attempt to yank the DNA out of as many dog and wolf fossils as he can. Those sequences will show exactly how the ancient canines relate to each other and to modern pooches. They’re the field’s best hope for getting firm answers to questions that have hounded them for decades.
And already, they have yielded a surprising discovery that could radically reframe the debate around dog domestication, so that the big question is no longer when it happened, or where, but how many times.
* * *
On the eastern edge of Ireland lies Newgrange, a 4,800-year-old monument that predates Stonehenge and the pyramids of Giza. Beneath its large circular mound and within its underground chambers lie many fragments of animal bones. And among those fragments, Dan Bradley from Trinity College Dublin found the petrous bone of a dog.
Press your finger behind your ear. That’s the petrous. It’s a bulbous knob of very dense bone that’s exceptionally good at preserving DNA. If you try to pull DNA out of a fossil, most of it will come from contaminating microbes and just a few percent will come from the bone’s actual owner. But if you’ve got a petrous bone, that proportion can be as high as 80 percent. And indeed, Bradley found DNA galore within the bone, enough to sequence the full genome of the long-dead dog.
Larson and his colleague Laurent Frantz then compared the Newgrange sequences with those of almost 700 modern dogs, and built a family tree that revealed the relationships between these individuals. To their surprise, that tree had an obvious fork in its trunk—a deep divide between two doggie dynasties. One includes all the dogs from eastern Eurasia, such as Shar Peis and Tibetan mastiffs. The other includes all the western Eurasian breeds, and the Newgrange dog.
The genomes of the dogs from the western branch suggest that they went through a population bottleneck—a dramatic dwindling of numbers. Larson interprets this as evidence of a long migration. He thinks that the two dog lineages began as a single population in the east, before one branch broke off and headed west. This supports the idea that dogs were domesticated somewhere in China.
But there’s a critical twist.
The team calculated that the two dog dynasties split from each other between 6,400 and 14,000 years ago. But the oldest dog fossils in both western and eastern Eurasia are older than that. Which means that when those eastern dogs migrated west into Europe, there were already dogs there.
Here’s the full story, as he sees it. Many thousands of years ago, somewhere in western Eurasia, humans domesticated grey wolves. The same thing happened independently, far away in the east. So, at this time, there were two distinct and geographically separated groups of dogs. Let’s call them Ancient Western and Ancient Eastern. Around the Bronze Age, some of the Ancient Eastern dogs migrated westward alongside their human partners, separating from their homebound peers and creating the deep split in Larson’s tree. Along their travels, these migrants encountered the indigenous Ancient Western dogs, mated with them (doggy style, presumably), and effectively replaced them.
Today’s eastern dogs are the descendants of the Ancient Eastern ones. But today’s western dogs (and the Newgrange one) trace most of their ancestry to the Ancient Eastern migrants. Less than 10 percent comes from the Ancient Western dogs, which have since gone extinct.
This is a bold story for Larson to endorse, not least because he himself has come down hard on other papers suggesting that cows, sheep, or other species were domesticated twice. “Any claims for more than one need to be substantially backed up by a lot of evidence,” he says. “Pigs were clearly domesticated in Anatolia and in East Asia. Everything else is once.” Well, except maybe dogs.
* * *
Other canine genetics experts think that Larson’s barking up the wrong tree. “I’m somewhat underwhelmed, since it’s based on a single specimen,” says Bob Wayne from the University of California, Los Angeles. He buys that there’s a deep genetic division between modern dogs. But, it’s still possible that dogs were domesticated just once, creating a large, widespread, interbreeding population that only later resolved into two distinct lineages.
In 2013, Wayne’s team compared the mitochondrial genomes (small rings of DNA that sit outside the main set) of 126 modern dogs and wolves, and 18 fossils. They concluded that dogs were domesticated somewhere in Europe or western Siberia, between 18,800 and 32,100 years ago. And genes aside, “the density of fossils from Europe tells us something,” says Wayne. “There are many things that look like dogs, and nothing quite like that in east Asia.”
Peter Savolainen from the KTH Royal Institute of Technology in Stockholm disagrees. By comparing the full genomes of 58 modern wolves and dogs, his team has shown that dogs in southern China are the most genetically diverse in the world. They must have originated there around 33,000 years ago, he says, before a subset of them migrated west 18,000 years later.
That’s essentially the same story that Larson is telling. The key difference is that Savolainen doesn’t buy the existence of an independently domesticated group of western dogs. “That’s stretching the data very much,” he says. Those Ancient Western dogs might have just been wolves, he says. Or perhaps they were an even earlier group of migrants from the east. “I think the picture must seem a bit chaotic,” he says understatedly. “But for me, it’s pretty clear. It must have happened in southern East Asia. You can’t interpret it any other way.”
Except, you totally can. Wayne does (“I’m certainly less dogmatic than Peter,” he says). Adam Boyko from Cornell University does, too: after studying the genes of village dogs—free-ranging mutts that live near human settlements—he argued for a single domestication in Central Asia, somewhere near India or Nepal. And clearly, Larson does as well.
Larson adds that his gene-focused peers are ignoring one crucial line of evidence—bones. If dogs originated just once, there should be a neat gradient of fossils with the oldest ones at the center of domestication and the youngest ones far away from it. That’s not what we have. Instead, archaeologists have found 15,000-year-old dog fossils in western Europe, 12,500-year-old ones in east Asia, and nothing older than 8,000 years in between.
“If we’re wrong, then how on earth do you explain the archaeological data?” says Larson. “Did dogs jump from East Asia to Western Europe in a week, and then go all the way back 4,000 years later?” No. A dual domestication makes more sense. Mietje Genompré, an archaeologist from the Royal Belgian Institute of Natural Sciences, agrees that the bones support Larson’s idea. “For me, it’s very convincing,” she says.
But even Larson is hedging his bets. When I ask him how strong his evidence is, he says, “Like, put a number on it? If was being bold, I’d say it’s a 7 out of 10. We lack the smoking gun.”
Why is this is so hard? Of all the problems that scientists struggle with, why has the origin of dogs been such a bitch to solve?
For starters, the timing is hard to pin down because no one knows exactly how fast dog genomes change. That pace—the mutation rate—underpins a lot of genetic studies. It allows scientists to compare modern dogs and ask: How long ago must these lineages have diverged in order to build up this many differences in their genes? And since individual teams use mutation rate estimates that are wildly different, it’s no wonder they’ve arrive at conflicting answers.
Regardless of the exact date, it’s clear that over thousands of years, dogs have mated with each other, cross-bred with wolves, travelled over the world, and been deliberately bred by humans. The resulting ebb and flow of genes has turned their history into a muddy, turbid mess—the homogeneous soup that Larson envisages.
Wolves provide no clarity. Grey wolves used to live across the entire Northern Hemisphere, so they could have potentially been domesticated anywhere within that vast range (although North America is certainly out). What’s more, genetic studies tell us that no living group of wolves is more closely related to dogs than any other, which means that the wolves that originally gave rise to dogs are now extinct. Sequencing living wolves and dogs will never truly reveal their shrouded past; it’d be, as Larson says, like trying to solve a crime when the culprit isn’t even on the list of suspects.
“The only way to know for sure is to go back in time,” he adds.
* * *
The study informally known as the Big Dog Project was born of frustration. Back in 2011, Larson was working hard on the origin of domestic pigs, and became annoyed that scientists studying dogs were getting less rigorous papers in more prestigious journals, simply because their subjects were that much more charismatic and media-friendly. So he called up his longstanding collaborator Keith Dobney. “Through gritted teeth, I said: We’re fucking doing dogs. And he said: I’m in.”
Right from the start, the duo realized that studying living dogs would never settle the great domestication debate. The only way to do that was to sequence ancient DNA from fossil dogs and wolves, throughout their range and at different points in history. While other scientists were studying the soup of dog genetics by tasting the finished product, Larson would reach back in time to taste it at every step of its creation, allowing him to definitively reconstruct the entire recipe.
In recent decades, scientists have become increasingly successful at extracting and sequencing strands of DNA from fossils. This ancient DNA has done wonders for our understanding of our own evolution. It showed, for example, how Europe was colonized 40,000 years ago by hunter-gatherers moving up from Africa, then 8,000 years ago by Middle Eastern farmers, and 5,000 years ago by horse-riding herders from the Russian steppes. “Everyone in Europe today is a blend of those three populations,” says Larson, who hopes to parse the dog genome in the same way, by slicing it into its constituent ingredients.
Larson originally envisaged a small project—just him and Dobney analyzing a few fossils. But he got more funding, collaborators, and samples than he expected. “It just kind of metastasized out of all proportion,” he says. He and his colleagues would travel the world, drilling into fossils and carting chips of bone back to Oxford. They went to museums and private collections. (“There was a guy up in York who had a ton of stuff in his garage.”) They grabbed bones from archaeological sites.
The pieces of bone come back to a facility in Oxford called the Palaeo-BARN—the Palaeogenomics and Bioarchaeology Research Network. When I toured the facility with Larson, we wore white overalls, surgical masks, oversoles, and purple gloves, to keep our DNA (and that of our skin microbes) away from the precious fossil samples. Larson called them ‘spacesuits.’ I was thinking ‘thrift-store ninja.’
In one room, the team shoves pieces of bone into a machine that pounds it with a small ball bearing, turning solid shards into fine powder. They then send the powder through a gauntlet of chemicals and filters to pull out the DNA and get rid of everything else. The result is a tiny drop of liquid that contains the genetic essence of a long-dead dog or wolf. Larson’s freezer contains 1,500 such drops, and many more are on the way. “It’s truly fantastic the kind of data that he has gathered,” says Savolainen.
True to his roots in archaeology, Larson isn’t ignoring the bones. His team photographed the skulls of some 7,000 prehistoric dogs and wolves at 220 angles each, and rebuilt them in virtual space. They can use a technique called geometric morphometrics to see how different features on the skulls have evolved over time.
The two lines of evidence—DNA and bones—should either support or refute the double domestication idea. It will also help to clear some confusion over a few peculiar fossils, such as a 36,000 year old skull from Goyet cave in Belgium. Genompré thinks it’s a primitive dog. “It falls outside the variability of wolves: it’s smaller and the snout is different,” she says. Others say it’s too dissimilar to modern dogs. Wayne has suggested that it represents an aborted attempt at domestication—a line of dogs that didn’t contribute to modern populations and is now extinct.
Maybe the Goyet hound was part of Larson’s hypothetical Ancient Western group, domesticated shortly after modern humans arrived in Europe. Maybe it represented yet another separate flirtation with domestication. All of these options are on the table, and Larson thinks he has the data to tell them apart. “We can start putting numbers on the difference between dogs and wolves,” he says. “We can say this is what all the wolves at this time period look like; does the Goyet material fall within that realm, or does it look like dogs from later on?”
Larson hopes to have the first big answers within six to twelve months. “I think it’ll clearly show that some things can’t be right, and will narrow down the number of hypotheses,” says Boyko. “It may narrow it down to one but I’m not holding my breath on that.” Wayne is more optimistic. “Ancient DNA will provide much more definitive data than we had in the past,” he says. “[Larson] convinced everyone of that. He’s a great diplomat.”
Indeed, beyond accumulating DNA and virtual skulls, Larson’s greatest skill is in gathering collaborators. In 2013, he rounded up as many dog researchers as he could and flew them to Aberdeen, so he could get them talking. “I won’t say there was no tension,” he says. “You go into a room with someone who has written something that sort of implies you aren’t doing very good science… there will be tension. But it went away very quickly. And, frankly: alcohol.”
“Everyone was like: You know what? If I’m completely wrong and I have to eat crow on this, I don’t give a shit. I just want to know.”
- April 27, 2016
- For the first time, scientists have demonstrated that an organism devoid of a nervous system is capable of learning. Biologists have succeeded in showing that a single-celled organism, the protist, is capable of a type of learning called habituation. This discovery throws light on the origins of learning ability during evolution, even before the appearance of a nervous system and brain. It may also raise questions as to the learning capacities of other extremely simple organisms such as viruses and bacteria.
For the first time, scientists have demonstrated that an organism devoid of a nervous system is capable of learning. A team from the Centre de Recherches sur la Cognition Animale (CNRS/Université Toulouse III — Paul Sabatier) has succeeded in showing that a single-celled organism, the protist Physarum polycephalum, is capable of a type of learning called habituation. This discovery throws light on the origins of learning ability during evolution, even before the appearance of a nervous system and brain. It may also raise questions as to the learning capacities of other extremely simple organisms such as viruses and bacteria. These findings are published in the Proceedings of the Royal Society B on 27 April 2016.
An ability to learn, and memory are key elements in the animal world. Learning from experiences and adapting behavior accordingly are vital for an animal living in a fluctuating and potentially dangerous environment. This faculty is generally considered to be the prerogative of organisms endowed with a brain and nervous system. However, single-celled organisms also need to adapt to change. Do they display an ability to learn? Bacteria certainly show adaptability, but it takes several generations to develop and is more a result of evolution. A team of biologists thus sought to find proof that a single-celled organism could learn. They chose to study the protist, or slime mold, Physarum polycephalum, a giant cell that inhabits shady, cool areas and has proved to be endowed with some astonishing abilities, such as solving a maze, avoiding traps or optimizing its nutrition. But until now very little was known about its ability to learn.
During a nine-day experiment, the scientists thus challenged different groups of this mold with bitter but harmless substances that they needed to pass through in order to reach a food source. Two groups were confronted either by a “bridge” impregnated with quinine, or with caffeine, while the control group only needed to cross a non-impregnated bridge. Initially reluctant to travel through the bitter substances, the molds gradually realized that they were harmless, and crossed them increasingly rapidly — behaving after six days in the same way as the control group. The cell thus learned not to fear a harmless substance after being confronted with it on several occasions, a phenomenon that the scientists refer to as habituation. After two days without contact with the bitter substance, the mold returned to its initial behavior of distrust. Furthermore, a protist habituated to caffeine displayed distrustful behavior towards quinine, and vice versa. Habituation was therefore clearly specific to a given substance.
Habituation is a form of rudimentary learning, which has been characterized in Aplysia (an invertebrate also called sea hare). This form of learning exists in all animals, but had never previously been observed in a non-neural organism. This discovery in a slime mold, a distant cousin of plants, fungi and animals that appeared on Earth some 500 million years before humans, improves existing understanding of the origins of learning, which markedly preceded those of nervous systems. It also offers an opportunity to study learning types in other very simple organisms, such as viruses or bacteria.
 This single cell, which contains thousands of nuclei, can cover an area of around a square meter and moves within its environment at speeds that can reach 5 cm per hour.
 See “Even single-celled organisms feed themselves in a ‘smart’ manner.” https://www.sciencedaily.com/releases/2010/02/100210164712.htm
 Mild tactile stimulation of the animal’s siphon normally causes the defensive reflex of withdrawing the branchiae. If the harmless tactile stimulation is repeated, this reflex diminishes and finally disappears, thus indicating habituation.
- Romain P. Boisseau, David Vogel, Audrey Dussutour. Habituation in non-neural organisms: evidence from slime moulds. Proceedings of the Royal Society B: Biological Sciences, 2016; 283 (1829): 20160446 DOI: 10.1098/rspb.2016.0446
Laughter? Now wait a minute! A real scientist should avoid any and all anthropomorphism, which is why hard-nosed colleagues often ask us to change our terminology. Why not call the ape’s reaction something neutral, like, say, vocalized panting? That way we avoid confusion between the human and the animal.
The term anthropomorphism, which means “human form,” comes from the Greek philosopher Xenophanes, who protested in the fifth century B.C. against Homer’s poetry because it described the gods as though they looked human. Xenophanes mocked this assumption, reportedly saying that if horses had hands they would “draw their gods like horses.” Nowadays the term has a broader meaning. It is typically used to censure the attribution of humanlike traits and experiences to other species. Animals don’t have “sex,” but engage in breeding behavior. They don’t have “friends,” but favorite affiliation partners.
Given how partial our species is to intellectual distinctions, we apply such linguistic castrations even more vigorously in the cognitive domain. By explaining the smartness of animals either as a product of instinct or simple learning, we have kept human cognition on its pedestal under the guise of being scientific. Everything boiled down to genes and reinforcement. To think otherwise opened you up to ridicule, which is what happened to Wolfgang Köhler, the German psychologist who, a century ago, was the first to demonstrate flashes of insight in chimpanzees.
Köhler would put a banana outside the enclosure of his star performer, Sultan, while giving him sticks that were too short to reach the fruit through the bars. Or he would hang a banana high up and spread boxes around, none of which were tall enough to reach the fruit. At first, Sultan would jump or throw things at the banana or drag a human by the hand toward it, hoping to use him as a footstool. If this failed, he would sit around without doing anything, pondering the situation, until he might hit on a solution. He’d jump up suddenly to put one bamboo stick inside another, making a longer stick. He’d also stack boxes to build a tower tall enough to attain his reward. Köhler described this moment as the “aha! experience,” not unlike Archimedes running through the streets shouting “Eureka!”
According to Köhler, Sultan showed insight by combining what he knew about boxes and sticks to produce a brand-new action sequence to take care of his problem. It all took place in his head, without prior rewards for his eventual solution. That animals may show mental processes closer to thinking than learning was so unsettling, though, that still today Köhler’s name is hissed rather than spoken in some circles. Naturally, one of his critics argued that the attribution of reasoning to animals was an “overswing of the theoretical pendulum” back “toward anthropomorphism.”
We still hear this argument, not so much for tendencies that we consider animalistic (everyone is free to speak of aggression, violence and territoriality in animals) but rather for traits that we like in ourselves. Accusations of anthropomorphism are about as big a spoiler in cognitive science as suggestions of doping are of athletic success. The indiscriminate nature of these accusations has been detrimental to cognitive science, as it has kept us from developing a truly evolutionary view. In our haste to argue that animals are not people, we have forgotten that people are animals, too.
This doesn’t mean that anything goes. Humans are incredibly eager to project feelings and experiences onto animals, often doing so uncritically. We go to beach hotels to swim with dolphins, convinced that the animals must love it as much as we do. We think that our dog feels guilt or that our cat is embarrassed when she misses a jump. Lately, people have fallen for the suggestion that Koko, the signing gorilla in California, is worried about climate change, or that chimpanzees have religion. As soon as I hear such claims, I contract my corrugator muscles (causing a frown) and ask for the evidence. Yes, dolphins have smiley faces, but since this is an immutable part of their visage, it fails to tell us anything about how they feel. Yes, dogs hide under the table when they have done something wrong, yet the most likely explanation is that they fear trouble.
Gratuitous anthropomorphism is distinctly unhelpful. However, when experienced field workers who follow apes around in the tropical forest tell me about the concern chimpanzees show for an injured companion, bringing her food or slowing down their walking pace, or report how adult male orangutans in the treetops vocally announce which way they expect to travel the next morning, I am not averse to speculations about empathy or planning. Given everything we know from controlled experiments in captivity, such as the ones I conduct myself, these speculations are not far-fetched.
To understand the resistance to cognitive explanations, I need to mention a third ancient Greek: Aristotle. The great philosopher put all living creatures on a vertical Scala Naturae, which runs from humans (closest to the gods) down toward other mammals, with birds, fish, insects and mollusks near the bottom. Comparisons up and down this vast ladder have been a popular scientific pastime, but all we have learned from them is how to measure other species by our standards. Keeping Aristotle’s scale intact, with humans on top, has been the unfailing goal.
But think about it: How likely is it that the immense richness of nature fits on a single dimension? Isn’t it more likely that each animal has its own cognition, adapted to its own senses and natural history? It makes no sense to compare our cognition with one that is distributed over eight independently moving arms, each with its own neural supply, or one that enables a flying organism to catch mobile prey by picking up the echoes of its own shrieks. Clark’s nutcrackers (members of the crow family) recall the location of thousands of seeds that they have hidden half a year before, while I can’t even remember where I parked my car a few hours ago. Anyone who knows animals can come up with a few more cognitive comparisons that are not in our favor. Instead of a ladder, we are facing an enormous plurality of cognitions with many peaks of specialization. Somewhat paradoxically, these peaks have been called “magic wells” because the more scientists learn about them, the deeper the mystery gets.
We now know, for example, that some crows excel at tool use. In an aviary at Oxford University in 2002, a New Caledonian crow named Betty tried to pull a little bucket with a piece of meat out of a transparent vertical pipe. All she had to work with was a straight metal wire, which didn’t do the trick. Undeterred, Betty used her beak to bend the straight wire into a hook to pull up the bucket. Since no one had taught Betty to do so, it was seen as an example of insight. Apart from dispelling the “birdbrain” notion with which birds are saddled, Betty achieved instant fame by offering proof of tool making outside the primate order. Since this capacity has by now been confirmed by other studies, including one on a cockatoo, we can safely do away with the 1949 book “Man the Tool-Maker” by the British anthropologist Kenneth Oakley, which declared tool fabrication humanity’s defining characteristic. Corvids are a technologically advanced branch on the tree of life with skills that often match those of primates like us.
Convergent evolution (when similar traits, like the wings of birds, bats and insects, appear independently in separate evolutionary branches) allows cognitive capacities to pop up at the most unexpected places, such as face recognition in paper wasps or deceptive tactics in cephalopods. When the males of some cuttlefish species are interrupted by a rival during courtship, they may trick the latter into thinking there is nothing to worry about. On the side of his body that faces his rival, the male adopts the coloring of a female, so that the other believes he is looking at two females. But the courting male keeps his original coloring on the female’s side of his body in order to keep her attention. This two-faced tactic, known as dual-gender signaling, suggests tactical skills of an order no one had ever suspected in a species so low on the natural scale. But of course, talk of “high” and “low” is anathema to biologists, who see every single organism as exquisitely adapted to its own environment.
Now let us return to the accusation of anthropomorphism that we hear every time a new discovery comes along. This accusation works only because of the premise of human exceptionalism. Rooted in religion but also permeating large areas of science, this premise is out of line with modern evolutionary biology and neuroscience. Our brains share the same basic structure with other mammals — no different parts, the same old neurotransmitters.
Brains are in fact so similar across the board that we study fear in the rat’s amygdala to treat human phobias. This doesn’t mean that the planning by an orangutan is of the same order as me announcing an exam in class and my students preparing for it, but deep down there is continuity between both processes. This applies even more to emotional traits.
This is why science nowadays often starts from the opposite end, assuming continuity between humans and animals, while shifting the burden of proof to those who insist on differences. Anyone who asks me to believe that a tickled ape, who almost chokes on his hoarse giggles, is in a different state of mind than a tickled human child has his work cut out for him.
In order to drive this point home, I invented the term “anthropodenial,” which refers to the a priori rejection of humanlike traits in other animals or animallike traits in us. Anthropomorphism and anthropodenial are inversely related: The closer another species is to us, the more anthropomorphism assists our understanding of this species and the greater will be the danger of anthropodenial. Conversely, the more distant a species is from us, the greater the risk that anthropomorphism proposes questionable similarities that have come about independently. Saying that ants have “queens,” “soldiers” and “slaves” is mere anthropomorphic shorthand without much of a connection to the way human societies create these roles.
THE key point is that anthropomorphism is not nearly as bad as people think. With species like the apes — aptly known as “anthropoids” (humanlike) — anthropomorphism is in fact a logical choice. After a lifetime of working with chimpanzees, bonobos and other primates, I feel that denial of the similarities is a greater problem than accepting them. Relabeling a chimpanzee kiss “mouth-to-mouth contact” obfuscates the meaning of a behavior that apes show under the same circumstances as humans, such as when they greet one another or reconcile after a fight. It would be like assigning Earth’s gravity a different name than the moon’s, just because we think Earth is special.
Unjustified linguistic barriers fragment the unity with which nature presents us. Apes and humans did not have enough time to independently evolve almost identical behavior under similar circumstances. Think about this the next time you read about ape planning, dog empathy or elephant self-awareness. Instead of denying these phenomena or ridiculing them, we would do better to ask “why not?”
One reason this whole debate is as heated as it is relates to its moral implications. When our ancestors moved from hunting to farming, they lost respect for animals and began to look at themselves as the rulers of nature. In order to justify how they treated other species, they had to play down their intelligence and deny them a soul. It is impossible to reverse this trend without raising questions about human attitudes and practices. We can see this process underway in the halting of biomedical research on chimpanzees and the opposition to the use of killer whales for entertainment.
Increased respect for animal intelligence also has consequences for cognitive science. For too long, we have left the human intellect dangling in empty evolutionary space. How could our species arrive at planning, empathy, consciousness and so on, if we are part of a natural world devoid of any and all steppingstones to such capacities? Wouldn’t this be about as unlikely as us being the only primates with wings?
Evolution is a gradual process of descent with modification, whether we are talking about physical or mental traits. The more we play down animal intelligence, the more we ask science to believe in miracles when it comes to the human mind. Instead of insisting on our superiority in every regard, let’s take pride in the connections.
There is nothing wrong with the recognition that we are apes — smart ones perhaps, but apes nonetheless. As an ape lover, I can’t see this comparison as insulting. We are endowed with the mental powers and imagination to get under the skin of other species. The more we succeed, the more we will realize that we are not the only intelligent life on earth.
Frans de Waal, a primatologist and professor of psychology at Emory University, is the author, most recently, of “Are We Smart Enough to Know How Smart Animals Are?” from which this essay is adapted.
A version of this op-ed appears in print on April 10, 2016, on page SR1 of the New York edition with the headline: What I Learned Tickling Apes.
A ilusão, que desempenhou um papel estrutural na constituição subjetiva da nossa espécie, pode já não estar ao nosso alcance
Talvez o mal-estar do nosso tempo seja o de que já não é possível escolher entre a pílula azul e a vermelha – ou entre continuar cego ou começar a enxergar o que está por trás da trama dos dias. O mal-estar se deve ao fato de que talvez já não exista a pílula azul – ou já não seja mais possível a ilusão, esta que desempenhou um papel estrutural na constituição subjetiva da nossa espécie ao longo dos milênios.
Se fosse um de nós o membro da resistência disposto a trair os companheiros, a negociar a rendição com as máquinas diante de um suculento filé num restaurante, aqui, agora, e não mais no final dos anos 90, o dilema poderia sofrer um deslocamento. O drama não seria enxergar o filé como filé, no sentido de poder acreditar que ele existe, assim como acreditar que o restaurante existe e que o cenário a que chamamos de mundo existe tal qual está diante dos nossos olhos.
Não. O dilema atual pode ser também este, mas só na medida em que também é outro. O drama é que acreditamos no filé, sabemos que ele existe e sabemos que é gostoso. Desejamos o filé, nos lambuzamos dele e temos prazer com ele. Ao olhar para ele, porém, não enxergamos apenas “o deserto do real”, mas algo muito mais encarnado e cada vez mais inescapável: enxergamos o boi.
É terrível enxergar o boi. E, como os mais sensíveis já descobriram, é impossível deixar de enxergá-lo. Nossa superpopulação de humanos extrapolou a lógica dos vivos, matar para comer. E impôs a escravização e a tortura cotidiana de outras espécies. Milhões de bois, galinhas e porcos nascem apenas para nos alimentar em campos de concentração aos quais damos nomes mais palatáveis. São sacrificados em holocaustos diários sem que nem mesmo tenham tido uma vida.
Animais confinados, presos, às vezes sem sequer poder se mover por uma existência inteira. Criamos profissões capazes de reconhecer em segundos se um pinto é macho ou fêmea para separar as fêmeas que viverão espremidas, muitas vezes sem conseguir sequer abrir as asas, botando ovos e depois virando bandejas no supermercado e jogar os machos para serem moídos ainda vivos no triturador de lixo. Escravidão e tortura/sacrifício e lixo, estes são os destinos que determinamos aos frangos.
Somos os nazistas das outras espécies – e produzimos holocaustos cotidianos
Somos os nazistas das outras espécies. E, se antes era possível ignorar, desqualificando a questão como algo menor ou coisa de “adoradores de alface”, a internet e a disseminação de informações tornaram impossível não enxergar o olho do boi. Ao olhar para o filé, o olho do boi nos olha de volta. O olho vidrado de quem está aterrorizado porque pressente que caminha no corredor da morte, o boi que se caga de medo enquanto é obrigado a dar o passo para o sacrifício, o boi que tenta escapar, mas não encontra saída. O olho do boi alcança até gente como eu, que pode ser colocada na categoria “adoradores de churrasco”.
A publicidade do século 20 perdeu a ressonância em tempos de internet. Porque a ilusão já não é possível. Nada era mais puro do que o leite branco tirado de uma vaquinha no pasto. Era fácil acreditar na imagem bucólica do alimento saudável. Nosso leite vinha do paraíso, de nosso passado rural perdido, da vida nos bosques de Walden. Assim como a longa série de produtos dele originados, como queijo, iogurte e manteiga.
Mas a vaca da imagem não existe. A real é a vaca que nasce em cativeiro, filha de outra escrava. A vaca que quase não se move, cuja existência consiste numa longa série de estupros por instrumentos que se enfiam pelo seu corpo para fecundá-la com o sêmen de outro escravo. Então ela engravida e engravida e engravida de bezerros que dela serão sequestrados para virar filés, para que suas tetas sigam dando leite delas tirados por outras máquinas. E, como sabemos disso, o leite que chega à nossa mesa já não pode mais ser branco, mas vermelho do horror da vaca cujo corpo virou um objeto, a vaca para quem cada dia é tortura, estupro e escravidão.
Para não beber sangue procuramos nas prateleiras leites à base de vegetais. Vegetais não gritam. Soja, apenas um dos tantos exemplos. Bifes de soja, hambúrgueres de soja, linguiças de soja, leite de soja. Mas como ignorar o desmatamento, a destruição de ecossistemas inteiros e com eles toda a vida que lá havia? Como ignorar que a soja pode ter sido plantada em terra indígena e que, enquanto ela vira mercadoria no supermercado, jovens Guarani Kaiowá se enforcam porque já não sabem como viver? Já não é possível fingir que não enxergamos isso. Assim, nem os veganos mais radicais podem se salvar do pecado original.
Os mais sensíveis sentem a textura de suas roupas e sabem que são costuradas com carne humana
Olhamos para nossas roupas e horrorizados sabemos que em algum lugar da linha globalizada de produção há nelas o sangue de crianças, homens e mulheres em regime de trabalho análogo à escravidão. Como o casal que morreu abraçado na fábrica de Bangladesh, gerando a fotografia que comoveu o mundo mas não eliminou o horror que seguiu em escala industrial. Ou mesmo de um imigrante boliviano enfiado num quarto insalubre trabalhando horas e horas por quase nada bem aqui ao lado. Mas os mais sensíveis sentem a textura de suas roupas e sabem que são costuradas com carne humana. E já não sabem como vesti-las. Nem sabem como dar brinquedos para seus filhos porque sabem que os bonecos, os carrinhos, os castelos e os dinossauros contêm neles o sangue das crianças sem infância, ou o de suas mães e pais.
Já não é possível levar crianças a zoológicos ou aquários porque sabemos que a única educação próxima da verdade que receberiam ali é a do horror a que os animais são submetidos para serem exibidos, por melhor que seja a imitação de seu habitat. Lembro uma reportagem que fui fazer num zoológico, planejada para ser divertida, e só pude contar, entre outros horrores, que o babuíno chamado Beto era mantido à custa de Valium, para evitar que arrancasse pedaços do próprio corpo. Mesmo dopado jogava-se contra as grades, atirava fezes nos visitantes e espancava a companheira. Pinky, a elefanta, vivia só. Seus dois companheiros tinham morrido ao cair no fosso tentando escapar do cativeiro. Sabemos hoje que os golfinhos e as baleias dos shows acrobáticos são escravos brutalizados para servir de entretenimento a humanos. E, desde que sabemos, aqueles que gozam com esses espetáculos de morte podem se descobrir não mais como famílias felizes num momento de lazer, como nas imagens dos folhetos publicitários, mas como hordas de sádicos.
No simples ato de acender a luz já existe a consciência de que estamos destruindo o mundo de alguém e de que nada mais será simples. Neste momento, para ficar apenas num exemplo, dezenas de milhares já perderam suas casas no rio Xingu, na Amazônia, para a operação da Hidrelétrica de Belo Monte. Povos indígenas que vivem na região atingida já não conseguem suportar o aumento exponencial de mosquitos desde que o lago da usina começou a encher, alterando o ecossistema e dizimando culturas, no que já foi denunciado pelo Ministério Público Federal como etnocídio. Os impactos mal começaram e, em menos de três meses, mais de 16 toneladas de peixes morreram. E talvez também esteja chegando ao fim o tempo em que ainda é aceitável contar vidas por toneladas, mesmo que seja a vida de peixes. Ou a morte de peixes. Um dedo no interruptor e uma cadeia de mortes. E agora também já sabemos disso.
Ao pedir um café e um pão com manteiga na padaria, nos implicamos numa cadeia de horrores
O tempo das ilusões acabou. Nenhum ato do nosso cotidiano é inocente. Ao pedir um café e um pão com manteiga na padaria, nos implicamos numa cadeia de horrores causados a animais e a humanos envolvidos na produção. Cada ato banal implica uma escolha ética – e também uma escolha política.
A descrição das atrocidades que cometemos rotineiramente pode aqui seguir por milhares de caracteres. Comemos, vestimos, nos entretemos, transportamos e nos transportamos à custa da escravidão, da tortura e do sacrifício de outras espécies e também dos mais frágeis da nossa própria espécie. Somos o que de pior aconteceu ao planeta e a todos que o habitam. A mudança climática já anuncia que não apenas tememos a catástrofe, mas nos tornamos a catástrofe. Desta vez, não só para todos os outros, mas também para nós mesmos.
Já não é possível a pílula azul – ou já não é possível à adesão às ilusões. Há várias implicações profundas numa época em que o conhecimento não liberta, mas condena. A começar, talvez, pela pergunta: quem é o inocente num mundo em que a inocência já não é possível? Seria o inocente o pior humano de todos? Seria o inocente um psicopata?
O que seremos nós, subjetivamente, agora que estamos condenados a enxergar? As redes sociais têm nos dado algumas pistas. O que a internet fez foi arrancar da humanidade as ilusões sobre si mesma. O cotidiano nas redes sociais nos mostrou a verdade que sempre esteve lá, mas era protegida – ou mediada – pelo mundo das aparências. Sobre isso já escrevi um artigo, chamado A boçalidade do mal, que pode ser lido aqui. As implicações de perder este véu tão arduamente tecido são profundas e recém começam a ser investigadas. O impacto sobre a subjetividade estrutural de nossa espécie é tremendo, exatamente porque é estrutural e desabou num espaço de tempo muito curto, quase num soluço.
Já não é mais possível pensar apenas em humanos quando se aborda o tema dos direitos
O que faremos diante da impossibilidade da pílula azul, a que garantia as ilusões? A ridicularização daqueles que levantam esse tema ainda é um caminho, mas convencem menos que no passado. Também a piada se torna anacrônica. As interrogações vêm mudando, e já não é possível afirmar, sem revelar considerável ignorância, inclusive sobre a ciência produzida, que os animais não têm vida mental nem emocional, são “irracionais”. Ou, lembrando um argumento religioso, “que não têm alma”. Toda a ideologia que um dia justificou a escravidão de humanos, até que foi questionada, derrubada e transformada numa mancha de crime e vergonha na história da humanidade, passou a ser confrontada também com relação aos animais.
Cada vez mais as outras espécies começam a ser vistas como diferentes – e não mais como inferiores. Assim, o que se coloca no campo da ética são questões fascinantes e muito mais espinhosas. Mesmo o termo “direitos humanos” passa a ser questionável, porque pensar apenas em “humanos” já não é mais possível. No momento em que nos tornamos a própria definição de catástrofe, o conceito de “espécie”, em sua expressão cultural, se desloca. Outras formas de compreender e nomear o lugar dos humanos ganham espaço no horizonte filosófico e no exercício da política.
Resta o cinismo, sempre o último reduto. Dizer que, diante de mais de 7 bilhões de seres humanos ocupando o planeta e crescendo, não há outra maneira a não ser comer e vestir exploração, escravidão e tortura é a afirmação mais óbvia. É a afirmação expandida usada para todas as desigualdades de direitos. Desde que não seja eu – ou os meus – os sacrificados, tudo bem.
Vale a pena dedicar um parágrafo aos cínicos, essa categoria que prolifera com o ímpeto de um Aedes aegypti no Brasil e no mundo. O cínico é aquele que olha com calculado enfado para todos os outros, porque ele acredita que entende o mundo como ele de fato é. Ele é o que sabe das coisas, o único esperto. Todos os outros são tolinhos com ideias irreais. O cínico é aquele que deixa o mundo como está. Mas talvez, neste momento, o cínico seja justamente o inocente. Sua inocência consiste em acreditar que a pílula azul ainda está disponível.
Como ser ético num mundo sem ilusões, em que cada ato implica na tortura e no sacrifício de um outro?
Há um preço para enxergar e, mesmo assim, assumir o extermínio cotidiano como dado, como parte intrínseca da condição de ser um humano. Nem toda a crescente gourmetização da comida, nem todas as narrativas ficcionais que contam uma história idílica sobre a origem daquele produto, nada ocultará esse preço. E nada reduzirá seu impacto subjetivo. Não é fácil viver na pele do algoz. Não é simples viver sabendo-se. Aquele que se olha no espelho e se enxerga carregará essa autoimagem consigo. E se tornará algo que já não é mais o mesmo.
Há uma imagem recente que pode dar algumas pistas sobre esse caminho. Numa praia da Argentina, um golfinho foi carregado por turistas. Alguns dizem que ainda estava vivo, outros que já estava morto. Vivo ou morto, os turistas preocuparam-se apenas com tirar selfies para postar nas redes sociais. O site de humor Sensacionalista postou: “Golfinho morre ao ser retirado do mar para turistas fazerem selfie e Deus anuncia recall do ser humano”.
Ainda assim, quem se horrorizou com a falta de horror alheia, à noite seguiu diante do olho do boi. O que fazer diante do olho do boi? Como ser ético num mundo sem ilusões, em que cada ato implica na tortura e no sacrifício de um outro, humano e não humano? Se somos os nazistas das outras espécies, quando não da mesma, aceitar que assim é não seria se tornar um Eichmann, o nazista julgado em Jerusalém que alegou apenas cumprir ordens, o homem tão banalmente ordinário que inspirou a filósofa Hannah Arendt a criar o conceito da “banalidade do mal”? Não seríamos, aos olhos do boi, todos Eichmann, justificando-nos pelo senso comum de que assim é e se faz o que é preciso para sobreviver? Se sim, o que implica viver assumidamente nesta pele?
Talvez estejamos, como espécie que se pensa, diante de um dos maiores dilemas éticos da nossa história. Sem poder optar pela pílula azul, a das ilusões, condenados à pílula vermelha, a que nos obriga a enxergar, como construir uma escolha que volte a incluir a ética? Como não paralisar diante do espelho, reduzidos ou ao horror ou ao cinismo, eliminando a possibilidade de transformação? Como nos mover?
Diante do filé que desejamos e do olho boi que nos interroga, há pelo menos uma hipótese cada vez mais forte: o inocente é um assassino.
Date: November 24, 2015
Source: Princeton University
Summary: Researchers report for the first time that the ‘living’ bridges army ants of the species Eciton hamatum build with their bodies are more sophisticated than scientists knew. The ants automatically assemble with a level of collective intelligence that could provide new insights into animal behavior and even help in the development of intuitive robots that can cooperate as a group.
Without any orders or direction, individuals from the rank and file instinctively stretch across the opening, clinging to one another as their comrades-in-arms swarm across their bodies. But this is no force of superhumans. They are army ants of the species Eciton hamatum, which form “living” bridges across breaks and gaps in the forest floor that allow their famously large raiding swarms to travel efficiently.
Researchers from Princeton University and the New Jersey Institute of Technology (NJIT) report for the first time that these structures are more sophisticated than scientists knew. The ants exhibit a level of collective intelligence that could provide new insights into animal behavior and even help in the development of intuitive robots that can cooperate as a group, the researchers said.
Ants of E. hamatum automatically form living bridges without any oversight from a “lead” ant, the researchers report in the journal Proceedings of the National Academy of the Sciences. The action of each individual coalesces into a group unit that can adapt to the terrain and also operates by a clear cost-benefit ratio. The ants will create a path over an open space up to the point when too many workers are being diverted from collecting food and prey.
“These ants are performing a collective computation. At the level of the entire colony, they’re saying they can afford this many ants locked up in this bridge, but no more than that,” said co-first author Matthew Lutz, a graduate student in Princeton’s Department of Ecology and Evolutionary Biology.
“There’s no single ant overseeing the decision, they’re making that calculation as a colony,” Lutz said. “Thinking about this cost-benefit framework might be a new insight that can be applied to other animal structures that people haven’t thought of before.”
The research could help explain how large groups of animals balance cost and benefit, about which little is known, said co-author Iain Couzin, a Princeton visiting senior research scholar in ecology and evolutionary biology, and director of the Max Planck Institute for Ornithology and chair of biodiversity and collective behavior at the University of Konstanz in Germany.
Previous studies have shown that single creatures use “rules of thumb” to weigh cost-and-benefit, said Couzin, who also is Lutz’s graduate adviser. This new work shows that in large groups these same individual guidelines can eventually coordinate group-wide, he said — the ants acted as a unit although each ant only knew its immediate circumstances.
“They don’t know how many other ants are in the bridge, or what the overall traffic situation is. They only know about their local connections to others, and the sense of ants moving over their bodies,” Couzin said. “Yet, they have evolved simple rules that allow them to keep reconfiguring until, collectively, they have made a structure of an appropriate size for the prevailing conditions.
“Finding out how sightless ants can achieve such feats certainly could change the way we think of self-configuring structures in nature — and those made by man,” he said.
Ant-colony behavior has been the basis of algorithms related to telecommunications and vehicle routing, among other areas, explained co-first author Chris Reid, a postdoctoral research associate at the University of Sydney who conducted the work while at NJIT. Ants exemplify “swarm intelligence,” in which individual-level interactions produce coordinated group behavior. E. hamatum crossings assemble when the ants detect congestion along their raiding trail, and disassemble when normal traffic has resumed.
Previously, scientists thought that ant bridges were static structures — their appearance over large gaps that ants clearly could not cross in midair was somewhat of a mystery, Reid said. The researchers found, however, that the ants, when confronted with an open space, start from the narrowest point of the expanse and work toward the widest point, expanding the bridge as they go to shorten the distance their compatriots must travel to get around the expanse.
“The amazing thing is that a very elegant solution to a colony-level problem arises from the individual interactions of a swarm of simple worker ants, each with only local information,” Reid said. “By extracting the rules used by individual ants about whether to initiate, join or leave a living structure, we could program swarms of simple robots to build bridges and other structures by connecting to each other.
“These robot bridges would exhibit the beneficial properties we observe in the ant bridges, such as adaptability to local conditions, real-time optimization of shape and position, and rapid construction and deconstruction without the need for external building materials,” Reid continued. “Such a swarm of robots would be especially useful in dangerous and unpredictable conditions, such as natural disaster zones.”
Radhika Nagpal, a professor of computer science at Harvard University who studies robotics and self-organizing biological systems, said that the findings reveal that there is “something much more fundamental about how complex structures are assembled and adapted in nature, and that it is not through a supervisor or planner making decisions.”
Individual ants adjusted to one another’s choices to create a successful structure, despite the fact that each ant didn’t necessarily know everything about the size of the gap or the traffic flow, said Nagpal, who is familiar with the research but was not involved in it.
“The goal wasn’t known ahead of time, but ‘emerged’ as the collective continually adapted its solution to the environmental factors,” she said. “The study really opens your eyes to new ways of thinking about collective power, and has tremendous potential as a way to think about engineering systems that are more adaptive and able to solve complex cost-benefit ratios at the network level just through peer-to-peer interactions.”
She compared the ant bridges to human-made bridges that automatically widened to accommodate heavy vehicle traffic or a growing population. While self-assembling road bridges may be a ways off, the example illustrates the potential that technologies built with the same self-assembling capabilities seen in E. hamatum could have.
“There’s a deep interest in creating robots that don’t just rely on themselves, but can exploit the group to do more — and self-assembly is the ultimate in doing more,” Nagpal said. “If you could have small simple robots that were able to navigate complex spaces, but could self-assemble into larger structures — bridges, towers, pulling chains, rafts — when they face something they individually did not have the ability to do, that’s a huge increase in power in what robots would be capable of.”
The spaces E. hamatum bridges are not dramatic by human standards — small rifts in the leaf cover, or between the ends of two sticks. Bridges will be the length of 10 to 20 ants, which is only a few centimeters, Lutz said. That said, E. hamatum swarms form several bridges during the course of a day, which can see the back-and-forth of thousands of ants.
“The bridges are something that happen numerous times every day. They’re creating bridges to optimize their traffic flow and maximize their time,” Lutz said.
“When you’re moving hundreds of thousands of ants, creating a little shortcut can save a lot of energy,” he said. “This is such a unique behavior. You have other types of ants forming structures out of their bodies, but it’s not such a huge part of their lives and daily behavior.”
The research also included Scott Powell, an army-ant expert and assistant professor of biology at George Washington University; Albert Kao, a postdoctoral fellow at Harvard who received his doctorate in ecology and evolutionary biology from Princeton in 2015; and Simon Garnier, an assistant professor of biological sciences at NJIT who studies swarm intelligence and was once a postdoctoral researcher in Couzin’s lab at Princeton.
To conduct their field experiments, Lutz and Reid constructed a 1.5-foot-tall apparatus with ramps on both sides and adjustable arms in the center with which they could adjust the size of the gap. They then inserted the apparatus into active E. hamatum raiding trails that they found in the forests of Barro Colorado Island, Panama. Because ants follow one another’s chemical scent, Lutz and Reid used sticks and leaves from the ants’ trail to get them to reform their column across the device.
Lutz and Reid observed how the ants formed bridges across gaps that were set at angles of 12, 20, 40 and 60 degrees. They gauged how much travel-distance the ants saved with their bridge versus the surface area (in centimeters squared) of the bridge itself. Twelve-degree angles shaved off the most distance (around 11 centimeters) while taking up the fewest workers. Sixty-degree angles had the highest cost-to-benefit ratio. Interestingly, the ants were willing to expend members for 20-degree angles, forming bridges up to 8 centimeters squared to decrease their travel time by almost 12 centimeters, indicating that the loss in manpower was worth the distance saved.
Lutz said that future research based on this work might compare these findings to the living bridges of another army ant species, E. burchellii, to determine if the same principles are in action.
The paper, “Army ants dynamically adjust living bridges in response to a cost-benefit trade-off,” was published Nov. 23 by Proceedings of the National Academy of Sciences. The work was supported by the National Science Foundation (grant nos. PHY-0848755, IOS0-1355061 and EAGER IOS-1251585); the Army Research Office (grant nos. W911NG-11-1-0385 and W911NF-14-1-0431); and the Human Frontier Science Program (grant no. RGP0065/2012).
- Chris R. Reid, Matthew J. Lutz, Scott Powell, Albert B. Kao, Iain D. Couzin, Simon Garnier. Army ants dynamically adjust living bridges in response to a cost–benefit trade-off. Proceedings of the National Academy of Sciences, 2015; 201512241 DOI: 10.1073/pnas.1512241112
For centuries it has been thought that culture is what distinguishes humans from other animals, but over the past decade this idea has been repeatedly called into question. Cultural variation has been identified in a growing number of species in recent years, ranging from primates to cetaceans. Chimpanzees, our closest living relatives, show the most diverse cultures aside from humans, most notably, in their use of a wide variety of tools.
The method traditionally used to establish the presence of culture in wild animals compares behavioural variation across populations and excludes all behavioural patterns that can be explained by genetic or environmental differences across sites. Nevertheless, it is impossible to conclusively rule out the influence of genetics and environmental conditions in geographically distant populations.
To circumnavigate this problem, researchers, led by Dr. Kathelijne Koops, took a new approach. “We compared neighbouring chimpanzee groups living under similar environmental conditions, which allows for the investigation of fine scale cultural differences, whilst keeping genetics constant,” said Koops.
She and colleagues from Kyoto University and Freie Universität Berlin compared the length of tools used for ‘ant-dipping’ between two neighbouring chimpanzee communities, M-group and S-group, in the Kalinzu Forest, Uganda. Dipping for army ants is one of the hallmark examples of culture in chimpanzees and involves the use of a stick to extract the highly aggressive army ants from their underground nests.
Previous research has shown that ant-dipping tool length varied across chimpanzee study sites in relation to the army ant species (Dorylus spp.) that were present. So Koops compared the availability of the different species of army ants and the length of dipping tools used in the two adjacent chimpanzee communities.
The researchers found that M-group tools were significantly longer than S-group tools, despite identical army ant species availability. Considering the lack of ecological differences between the two communities, the tool length difference was concluded to be cultural. “Our findings highlight how cultural knowledge can generate small-scale cultural diversification in neighbouring groups,” said Koops.
“Given the close evolutionary relationship between chimpanzees and humans, insights into what drives cultural diversification in our closest living relatives will in turn shed light on how cultural differences emerge and are maintained between adjacent groups in human societies,” said Koops, who conducted the work at Cambridge University’s Division of Biological Anthropology and at Zurich University’s Anthropological Institute and Museum.
The research is published today in the Nature journal Scientific Reports.
Primatas que usam lanças podem fornecer indícios sobre origem das sociedades humanas
Na quente savana senegalesa se encontra o único grupo de chimpanzés que usa lanças para caçar animais com os quais se alimenta. Um ou outro grupo de chimpanzés foi visto portando ferramentas para a captura de pequenos mamíferos, mas esses, na comunidade de Fongoli, caçam regularmente usando ramos afiados. Esse modo de conseguir alimento é um uso cultural consolidado para esse grupo de chimpanzés.
Além dessa inovação tecnológica, em Fongoli ocorre também uma novidade social que os distingue dos demais chimpanzés estudados na África: há mais tolerância, maior paridade dos sexos na caça e os machos mais corpulentos não passam com tanta frequência por cima dos interesses dos demais, valendo-se de sua força. Para os pesquisadores que vêm observando esse comportamento há uma década esses usos poderiam, além disso, oferecer pistas sobre a evolução dos ancestrais humanos.
“São a única população não humana conhecida que caça vertebrados com ferramentas de forma sistemática, por isso constituem uma fonte importante para a hipótese sobre o comportamento dos primeiros hominídeos, com base na analogia”, explicam os pesquisadores do estudo no qual formularam suas conclusões depois de dez anos observando as caçadas de Fongoli. Esse grupo, liderado pela antropóloga Jill Pruetz, considera que esses animais são um bom exemplo do que pode ser a origem dos primeiros primatas eretos sobre duas patas.
Na sociedade Fongoli as fêmeas realizam exatamente a metade das caçadas com lança. Graças à inovação tecnológica que representa a conversão de galhos em pequenas lanças com as quais se ajudam para caçar galagos – pequenos macacos muito comuns nesse entorno –, as fêmeas conseguem certa independência alimentar. Na comunidade de Gombe, que durante muitos anos foi estudada por Jane Goodall, os machos arcam com cerca de 90% do total das presas; em Fongoli, somente 70%. Além disso, em outros grupos de chimpanzés os machos mais fortes roubam uma de cada quatro presas caçadas pelas fêmeas (sem ferramentas): em Fongoli, apenas 5%.
“Em Fongoli, quando uma fêmea ou um macho de baixo escalão captura uma presa, permitem que ele fique com ela e a coma. Em outros lugares, o macho alfa ou outro macho dominante costuma tomar-lhe a presa. Assim, as fêmeas obtêm pouco benefício da caça, se outro chimpanzé lhe tira sua presa”, afirma Pruetz. Ou seja, o respeito dos machos de Fongoli pelas presas obtidas por suas companheiras serviria de incentivo para que elas se decidam a ir à caça com mais frequência do que as de outras comunidades. Durante esses anos de observação, praticamente todos os chimpanzés do grupo – cerca de 30 indivíduos – caçaram com ferramentas,
O clima seco faz com que os macacos mais acessíveis em Fongoli sejam os pequenos galagos, e não os colobos vermelhos – os preferidos dos chimpanzés em outros lugares da África –, que são maiores e difíceis de capturar por outros que não sejam os machos mais rápidos e corpulentos. Quase todos os episódios de caça com lanças observados (três centenas) se deram nos meses úmidos, nos quais outras fontes de alimento são escassas.
A savana senegalesa, com poucas árvores, é um ecossistema que tem uma importante semelhança com o cenário em que evoluíram os ancestrais humanos. Ao contrário de outras comunidades africanas, os chimpanzés de Fongoli passam a maior parte do tempo no chão, e não entre os galhos. A excepcional forma de caça de Fongoli leva os pesquisadores a sugerir em seu estudo que os primeiros hominídeos provavelmente intensificaram o uso de ferramentas tecnológicas para superar as pressões ambientais, e que eram até mesmo “suficientemente sofisticados a ponto de aperfeiçoar ferramentas de caça”.
“Sabemos que o entorno tem um impacto importante no comportamento dos chimpanzés”, afirma o primatólogo Joseph Call, do Instituto Max Planck. “A distribuição das árvores determina o tipo de caça: onde a vegetação é mais frondosa, a caçada é mais cooperativa em relação a outros entornos nos quais é mais fácil seguir a presa, e eles são mais individualistas”, assinala Call.
No entanto, Call põe em dúvida que essas práticas de Fongoli possam ser consideradas caçadas com lança propriamente ditas, já que para ele lembram mais a captura de formigas e cupins usando palitos, algo mais comum entre os primatas. “A definição de caça que os pesquisadores estabelecem em seu estudo não se distingue muito do que fazem colocando um raminho em um orifício para conseguir insetos para comer”, diz Call. Os chimpanzés de Fongoli cutucam com paus os galagos quando eles se escondem em cavidades das árvores para forçá-los a sair e, uma vez fora, lhes arrancam a cabeça com uma mordida. “É algo que fica entre uma coisa e a outra”, argumenta.
Esses antropólogos acreditam que o achado permite pensar que os primeiros hominídeos eretos também usavam lanças
Pruetz responde a esse tipo de crítica dizendo que se trata de uma estratégia para evitar que o macaco os morda ou escape, uma situação muito diferente daquela de colocar um galho em um orifício para capturar bichos. Se for o mesmo, argumentam Pruetz e seus colegas, a pergunta é “por que os chimpanzés de outros grupos não caçam mais”.
Além do caso particular, nem sequer está encerrado o debate sobre se os chimpanzés devem ser considerados modelos do que foram os ancestrais humanos. “Temos de levar em conta que o bonobo não faz nada disso e é tão próximo de nós como o chimpanzé”, defende Call. “Pegamos o chimpanzé por que nos cai bem para assinalar determinadas influências comuns. É preciso ter muito cuidado e não pesquisar a espécie dependendo do que queiramos encontrar”, propõe.
April 24, 2015 – John Hartigan
“Scientists say…” It’s interesting what natural science research starts making the rounds on social media. Mostly on diet or health broadly, and increasingly concerning climate change. On rare occasion—as over the past few days—some reports surface that offer insight into the circulating clutter itself, as in “cute dog” photos. In this instance, they’re opportunities to glimpse changing understandings of big topics, like domestication and evolution.
Links for two articles recently popped up in my Twitter feed: “The Science of Puppy-Dog Eyes” (NYTimes, 4/21/14) and “The Guilty Looking Companion,” Scientific American(4/20/15), both treating the gazing behavior of dogs and its various effects on humans. The first, by Jan Hoffman, reported on a study published in Science (in a themed-column on evolution), titled, “Dogs hijack the human bonding pathway.” The second, by Julie Hecht, “The Guilty Looking Companion,” builds off an article in Behavioral Processes, on a tangled question: “Are owners’ reports of their dogs’ ‘guilty look’ influenced by the dogs’ action and evidence of the misdeed?” Both suggest a far more agential companion species than many people might’ve suspected, but more importantly they each complicate stock domestication narratives suggesting it was something we simply did to them. They also suggest opportunities for extending social analysis beyond the human.
As the title of the Science article suggests, dogs were possibly canny drivers of domestication: “dogs became domesticated in part by adapting to human means of communication: eye contact.” In particular, the speculation is that dogs cleverly “utilized a natural system meant for bonding a parent with his or her child.” Evolutionarily, “the challenge for dogs may simply have been to express a behavioral (and morphological) repertoire that mimicked the cues that elicit caregiving toward our own young. Indeed, these juvenile characteristics of dogs are known to carry a selective advantage with respect to human preferences.” So dogs wile their way into our good graces by coopting the cuteness channel we have for children. To complicate agency a bit further, this seems to all hinge on a bidirectional hormonal mechanism: people and dogs both develop heightened, pleasurable levels of oxytocin from protracted gazing into each other’s eyes. “These findings suggest not only an interspecific effect of oxytocin, but also the exciting possibility of a feedback loop,” since “shifts in oxytocin concentration in a dog might elicit similar changes in a human and vice-versa—just as when a mother bonds with her infant.” Domestication just got a good deal more interesting.
“The guilty looking companion” takes up the theme of sociality and how social bonds are respectively maintained in various species, but also how humans might be duped by our tendency to anthropomorphize dogs as possessing a subjective state approximating shame. The reparative behaviors of appeasement and reconciliation that maintain relationships, practiced by many species, when manifested by dogs, reads easily, to us, as “guilt.” But through a fascinating series of experiments, researchers countered that these canine gestures are just “cohesive displays,” which operate “to reduce conflict, diffuse tension, and reinforce social bonds.” Dogs are not responding to ameliorating a subjective sense of shame at transgressing rules; they are instead “incredibly sensitive to environmental and social cues.” If there’s furniture torn or overturned, the owner is looking for someone to chastise—better grovel or cringe. These behavior are very effective, according to surveys of dog owners, who withhold punishments in the wake of such displays. But Hecht concludes with a caution: “It might just be that we’re anthropomorphizing,” in reference to the viral spew of “dog shamming” photos. “Which, in this case, might not be good for us or our dogs.” Indeed, but what is even more valuable here is the perspective opened up onto thinking about parallel and converging forms of species sociality, beyond the question of who is domesticating who.
On that topic, another recently published science article pursues just these openings, though unfortunately it does not seem to be circulating widely at all. “Testing the myth: Tolerant dogs and aggressive wolves,” in Proceedings B (Royal Society Publishing) reports on findings that indicate “a steeper dominance hierarchy in dogs than in wolves.” While “tolerance” is supposed to be the character trait “selected for,” dogs appear far more aggressive and uncooperative with conspecifics than wolves. The problem with “all domestication theories” to date is that they’ve ignored “apparently contradictory behaviours…observed in dogs and wolf packs.” There’s an enormous amount to this piece, but it may come down to “face,” as Erving Goffman developed the concept. “Visual communication in dogs is somewhat impaired due to their reduced visual (facial as well as bodily) expressions,” which “might lead to an inability to control conflicts in close quarters.” Wolves are far more articulate in reading both gaze and facial features in conspecific communications. Range et al write, “Although dogs and wolves seem to use the same signals overall, it is possible that dogs do not use them as appropriately as wolves”—i.e., they haven’t refined the etiquette of conspecific communications quite as well, though they’re very good at circumventing our conspecific gaze signaling tendencies.
But that “wolves appear tolerant, attentive, and at the same time cooperative towards pack members” is in stark “contrast to the starting point of several recent domestication hypotheses.” Free-ranging dogs—constituting about 76-83% of the global dog population!!—not so much. So the questions swirl as to dogs’ cognitive and emotional processes underlying their intraspecific sociality and how that variously aligns with ours, in the deep past and today.
Galinhas são animais de visão, diz a ciência. Perto delas, somos uns daltônicos.
Cientistas descobriram que suas retinas têm cinco cones sensíveis à cor. Humanos têm só três, que enxergam comprimentos de vermelho, azul e verde –o resto é mistura. Galinhas nos superam com um cone para violeta e alguns comprimentos ultravioleta e com um quinto receptor, ainda pouco compreendido.
|Galinha da Faculdade de Medicina Veterinária e Zootecnia da USP, no campus de Pirassununga|
Além disso, no ano passado cientistas de Princeton (EUA) mostraram que os átomos do olho da galinha se organizam num estado da matéria inédito na biologia, com propriedades tanto de cristal sólido quanto de líquido. Tal arranjo permite que cores sejam recebidas de forma muito nítida.
Foi assim que o olho da galinha foi parar na revista científica “Physical Review”, entre artigos sobre temas da física como dissipação de energia ou mecânica quântica.
Isso tudo faz com que seja difícil imaginarmos como uma galinha vê cores –só sabemos que é bem mais intenso e, digamos, psicodélico.
Por que a evolução deixou o olho da galinha assim? É uma boa pergunta. As respostas passam pela importância das cores para ela –pense, por exemplo, na plumagem colorida dos parceiros sexuais.
(Reuters) – Just as Bostonians moving to Tokyo ditch “grapefruit” and adopt “pamplemousse,” so chimps joining a new troop change their calls to match those of their new troop, scientists reported on Thursday in the journal Current Biology.
The discovery represents the first evidence that animals besides humans can replace the vocal sounds their native group uses for specific objects – in the chimps’ case, apples – with those of their new community.
One expert on chimp vocalizations, Bill Hopkins of Yerkes National Primate Research Center in Atlanta, who was not involved in the study, questioned some of its methodology, such as how the scientists elicited and recorded the chimps’ calls, but called it “interesting work.”
Chimps have specific grunts, barks, hoots and other vocalizations for particular foods, for predators and for requests such as “look at me,” which members of their troop understand.
Earlier studies had shown that these primates, humans’ closest living relatives, can learn totally new calls in research settings through intensive training. And a 2012 study led by Yerkes’ Hopkins showed that young chimps are able to pick up sounds meaning “human, pay attention to me,” from their mothers.
But no previous research had shown that chimps can replace a call they had used for years with one used by another troop. Instead, primatologists had thought that sounds referring to objects in the environment were learned at a young age and essentially permanent, with any variations reflecting nuances such as how excited the animal is about, say, a banana.
In the new research, scientists studied adult chimpanzees that in 2010 had been moved from a safari park in the Netherlands to Scotland’s Edinburgh Zoo, to live with nine other adults in a huge new enclosure.
It took three years, and the formation of strong social bonds among the animals, but the grunt that the seven Dutch chimps used for “apple” (a favorite food) changed from a high-pitched eow-eow-eow to the lower-pitched udh-udh-udh used by the six Scots, said co-author Simon Townsend of the University of Zurich. The change was apparent even to non-chimp-speakers (scientists).
“We showed that, through social learning, the chimps could change their vocalizations,” Townsend said in an interview. That suggests human language isn’t unique in using socially-learned sounds to signify objects.
Unanswered is what motivated the Dutch chimps to sound more like the Scots: to be better understood, or to fit in by adopting the reining patois?
(Reporting by Sharon Begley; Editing by Nick Zieminski)
Date: November 5, 2014
Source: Le Centre national de la recherche scientifique (CNRS)
The ability to build up knowledge over generations, called cumulative culture, has given mankind language and technology. While it was thought to be limited to humans until now, researchers from the Laboratoire de psychologie cognitive (CNRS/AMU), working in collaboration with colleagues at the University of Edinburgh (UK), have recently found that baboons are also capable of cumulative culture. Their findings are published in Proceedings of the Royal Society B on 5 November 2014.
Humankind is capable of great accomplishments, such as sending probes into space and eradicating diseases; these achievements have been made possible because humans learn from their elders and enrich this knowledge over generations. It was previously thought that this cumulative aspect of culture — whereby small changes build up, are transmitted, used and enriched by others — was limited to humans, but it has now been observed in another primate, the baboon.
While it is clear that monkeys like chimpanzees learn many things from their peers, each individual seems to start learning from scratch. In contrast, humans use techniques that evolve and improve from one generation to the next, and also differ from one population to another. The origin of cumulative culture in humans has therefore remained a mystery to scientists, who are trying to identify the necessary conditions for this cultural accumulation.
Nicolas Claidière and Joël Fagot, of the Laboratoire de psychologie cognitive, conducted the present study at the CNRS Primatology Center in Rousset, southeastern France. Baboons live in groups there and have free access to an area with touch screens where they can play a “memory game” specifically designed for the study. The screen briefly displays a grid of 16 squares, four of which are red and the others white. This image is then replaced by a similar grid, but composed of only white squares, and the baboons must touch the four squares that were previously red. Phase one of the experiment started with a task-learning period in which the position of the four red squares was randomized. Phase two comprised a kind of visual form of “Chinese whispers” wherein information was transmitted from one individual to another. In this second phase, a baboon’s response (the squares touched on the screen) was used to generate the next grid pattern that the following baboon had to memorize and reproduce, and so on for 12 “generations.”
The researchers, in collaboration with Simon Kirby and Kenny Smith from the University of Edinburgh, noted that baboons performed better in the phase involving a transmission chain (compared with random testing, which continued throughout the period of the experiment): success rate (1) increased from 80% to over 95%. Due to errors by the baboons, the patterns evolved between the beginning and the end of each chain. Yet to the surprise of researchers, the random computer-generated patterns were gradually replaced by “tetrominos” (Tetris®-like shapes composed of four adjacent squares), even though these forms represent only 6.2% of possible configurations! An even more surprising result was that the baboons’ performance on these rare shapes was poor during random testing, but increased throughout the transmission chain, during which the tetrominos accumulated. Moreover, when the experiment was replicated several times, the starting patterns did not lead to the same set of tetrominos. This study shows that, like humans, baboons have the ability to transmit and accumulate changes over “cultural generations” and that these incremental changes, which may differ depending on the chain, become structured and more efficient.
Researchers have ensured that all the necessary conditions were present to observe a type of cumulative cultural evolution in non-human primates, with its three characteristic properties (progressive increase in performance, emergence of systematic structures, and lineage specificity). These results show that cumulative culture does not require specifically human capacities, such as language. So why have no examples of this type of cultural evolution been clearly identified in the wild? Perhaps because the utilitarian dimension of non-human primate culture (e.g., the development of tools) hinders such evolution.
(1) The task was considered successful if at least 3 out of 4 squares were correctly memorized.
- N. Claidière, K. Smith, S. Kirby, J. Fagot. Cultural evolution of systematically structured behaviour in a non-human primate. Proceedings of the Royal Society B, November 2014 DOI: 10.1098/rspb.2014.1541
West African chimpanzees will search far and wide to find Alchornea hirtella, a spindly shrub whose straight shoots provide the ideal tools to hunt aggressive army ants in an ingenious fashion, new research shows.
The plant provides the animals with two different types of tool, a thicker shoot for ‘digging’ and a more slender tool for ‘dipping’.
On locating an army ant colony, chimpanzees will dig into the nest with the first tool – aggravating the insects. They then dip the second tool into the nest, causing the angry ants to swarm up it. Once the slender shoot is covered in ants, the chimpanzees pull it out and wipe their fingers along it: scooping up the ants until they have a substantial handful that goes straight into the mouth in one deft motion.
This technique – ‘ant dipping’ – was previously believed to be a last resort for the hungry apes, only exploited when the animal’s preferred food of fruit couldn’t be found. But the latest study, based on over ten years of data, shows that, in fact, army ants are a staple in the chimpanzee diet – eaten all year round regardless of available sources of fruit. Ants may be an important source of essential nutrients not available in the typical diet, say researchers, as well as a potential source of protein and fats.
The new research, published today in the American Journal of Primatology, was led by Dr Kathelijne Koops from the University of Cambridge’s Division of Biological Anthropology and Junior Research Fellow of Homerton College.
This video shows a male chimpanzee looking on at a female who is using an ant-dipping tool (Kalinzu Forest, Uganda).
“Ant dipping is a remarkable feat of problem-solving on the part of chimpanzees,” said Koops. “If they tried to gather ants from the ground with their hands, they would end up horribly bitten with very little to show for it. But by using a tool set, preying on these social insects may prove as nutritionally lucrative as hunting a small mammal – a solid chunk of protein.”
Koops points out that if Alchornea hirtella is nowhere to be found, chimps will fashion tools from other plants – but seemingly only after an exhaustive search for their preferred tool provider.
Previous research has shown that chimpanzees will actually select longer tools for faster, more aggressive types of army ants. The average ‘dipping’ tool length across the study was 64 centimetres, but dipping tools got up to 76 cm.
The question for Koops is one of animal culture: how do chimpanzees acquire knowledge of such sophisticated techniques?
“Scientists have been working on ruling out simple environmental and genetic explanations for group differences in behaviours, such as tool use, and the evidence is pointing strongly towards it being cultural,” said Koops. “They probably learn tool use behaviours from their mother and others in the group when they are young.”
The research for the ant-dipping study – which took place in Guinea’s Nimba mountains – proved challenging, as the chimpanzees were not habituated to people – so the team acted almost as archaeologists, studying ‘exploited’ ants nests to measure abandoned tool sets and “sifting through faeces for ants heads”.
To further study these illusive creatures, Koops set up cameras to take extensive video footage of the chimpanzees and their tool use. In doing so, she managed to capture a chimpanzee who has constructed a tool with which to investigate the camera itself – prodding it curiously and then sniffing the end of the tool (VIDEO 1).
“This study is part of a big ongoing research project. The next stages will involve looking at social opportunities to learn: how much time do youngsters spend within arm’s length of other individuals; how much time do they spend close to their mother; as well as innate predispositions to explore and engage with objects,” said Koops.
A video clip from the Kalinzu Forest in Uganda, where Koops is currently conducting comparative studies on East African chimpanzees, captures a male chimpanzee seemingly looking on enviously at a female who has managed to construct a much better dipping tool than his own and is feasting heartily as a consequence (VIDEO 2). Koops suggests this kind of observing of other individuals may lead to learning within a chimpanzee community.
“By studying our closest living relatives we gain a window into the evolutionary past which allows us to shed light on the origins of human technology and material culture,” added Koops.
A link to the paper can be found here: http://onlinelibrary.wiley.com/journal/10.1002/(ISSN)1098-2345/earlyview
Date: October 13, 2014
Source: University of Tennessee
Recent studies have found that crocodiles and their relatives are highly intelligent animals capable of sophisticated behavior such as advanced parental care, complex communication and use of tools for hunting.
New University of Tennessee, Knoxville, research published in the journal Ethology Ecology and Evolution shows just how sophisticated their hunting techniques can be.
Vladimir Dinets, a research assistant professor in UT’s Department of Psychology, has found that crocodiles work as a team to hunt their prey. His research tapped into the power of social media to document such behavior.
Studying predatory behavior by crocodiles and their relatives such as alligators and caimans in the wild is notoriously difficult because they are ambush hunters, have slow metabolisms and eat much less frequently than warm-blooded animals. In addition, they are mostly nocturnal and often hunt in murky, overgrown waters of remote tropical rivers and swamps. Accidental observations of their hunting behavior are often made by non-specialists and remain unpublished or appear in obscure journals.
To overcome these difficulties, Dinets used Facebook and other social media sites to solicit eyewitness accounts from amateur naturalists, crocodile researchers and nonscientists working with crocodiles. He also looked through diaries of scientists and conducted more than 3,000 hours of observations himself.
All that work produced just a handful of observations, some dating back to the 19th century. Still, the observations had something in common — coordination and collaboration among the crocodiles in hunting their prey.
“Despite having been made independently by different people on different continents, these records showed striking similarities. This suggests that the observed phenomena are real, rather than just tall tales or misinterpretation,” said Dinets.
Crocodiles and alligators were observed conducting highly organized game drives. For example, crocodiles would swim in a circle around a shoal of fish, gradually making the circle tighter until the fish were forced into a tight “bait ball.” Then the crocodiles would take turns cutting across the center of the circle, snatching the fish.
Sometimes animals of different size would take up different roles. Larger alligators would drive a fish from the deeper part of a lake into the shallows, where smaller, more agile alligators would block its escape. In one case, a huge saltwater crocodile scared a pig into running off a trail and into a lagoon where two smaller crocodiles were waiting in ambush — the circumstances suggested that the three crocodiles had anticipated each other’s positions and actions without being able to see each other.
“All these observations indicate that crocodilians might belong to a very select club of hunters — just 20 or so species of animals, including humans — capable of coordinating their actions in sophisticated ways and assuming different roles according to each individual’s abilities. In fact, they might be second only to humans in their hunting prowess,” said Dinets.
Dinets said more observations are needed to better understand what exactly the animals are capable of. “And these observations don’t come easily,” he said.
Previous research by Dinets discovered that crocodiles are able to climb trees and use lures such as sticks to hunt prey. More of his crocodile research can be found in his book “Dragon Songs.”
- Vladimir Dinets. Apparent coordination and collaboration in cooperatively hunting crocodilians. Ethology Ecology & Evolution, 2014; 1 DOI:10.1080/03949370.2014.915432
Date: October 7, 2014
Source: Acoustical Society of America (ASA)
From barks to gobbles, the sounds that most animals use to communicate are innate, not learned. However, a few species, including humans, can imitate new sounds and use them in appropriate social contexts. This ability, known as vocal learning, is one of the underpinnings of language.
Vocal learning has also been observed in bats, some birds, and cetaceans, a group that includes whales and dolphins. But while avian researchers have characterized vocal learning in songbirds down to specific neural pathways, studying the trait in large marine animals has presented more of a challenge.
Now, University of San Diego graduate student Whitney Musser and Hubbs-SeaWorld Research Institute senior research scientist Dr. Ann Bowles have found that killer whales (Orcinus orca) can engage in cross-species vocal learning: when socialized with bottlenose dolphins, they shifted the types of sounds they made to more closely match their social partners. The results, published in The Journal of the Acoustical Society of America, suggest that vocal imitation may facilitate social interactions in cetaceans.
Killer whales have complex vocal repertoires made up of clicks, whistles and pulsed calls — repeated brief bursts of sound punctuated with silence. The acoustic features of these vocalizations, such as their duration, pitch and pulse pattern, vary across social groups. Whales that are closely related or live together produce similar pulsed calls that carry vocal characteristics distinct to the group, known as a dialect.
“There’s been an idea for a long time that killer whales learn their dialect, but it isn’t enough to say they all have different dialects so therefore they learn. There needs to be some experimental proof so you can say how well they learn and what context promotes learning,” said Bowles.
Testing vocal learning ability in social mammals usually requires observing the animal in a novel social situation, one that might stimulate them to communicate in new ways. Bottlenose dolphins provide a useful comparison species in this respect: they make generally similar sounds but produce them in different proportions, relying more on clicks and whistles than the pulsed calls that dominate killer whale communication.
“We had a perfect opportunity because historically, some killer whales have been held with bottlenose dolphins,” said Bowles. By comparing old recordings of vocalization patterns from the cross-socialized subjects with recordings of killer whales and bottlenose dolphins housed in same-species groups, Bowles and her team were able to evaluate the degree to which killer whales learned vocalization patterns from their cross-species social partners.
All three killer whales that had been housed with dolphins for several years shifted the proportions of different call types in their repertoire to more closely match the distribution found in dolphins — they produced more clicks and whistles and fewer pulsed calls. The researchers also found evidence that killer whales can learn completely new sounds: one killer whale that was living with dolphins at the time of the experiment learned to produce a chirp sequence that human caretakers had taught to her dolphin pool-mates before she was introduced to them.
Vocal learning skills alone don’t necessarily mean that killer whales have language in the same way that humans do. However, they do indicate a high level of neural plasticity, the ability to change circuits in the brain to incorporate new information. “Killer whales seem to be really motivated to match the features of their social partners,” said Bowles, though the adaptive significance of the behavior is not yet known.
There are immediate reasons to study the vocal patterns of cetaceans: these marine mammals are threatened by human activities through competition for fishery resources, entanglement in fishing gear, collisions with vessels, exposure to pollutants and oil spills and, ultimately, shrinking habitats due to anthropogenic climate change. If their social bonds are closely linked to their vocalizations, killer whales’ ability to survive amidst shifting territories and social groups may be tied to their ability to adapt their communication strategies.
“It’s important to understand how they acquire [their vocalization patterns], and lifelong, to what degree they can change it, because there are a number of different [cetacean] populations on the decline right now,” said Bowles. “And where killer whales go, we can expect other small whale species to go — it’s a broader question.”
- Whitney B. Musser, Ann E. Bowles, Dawn M. Grebner, and Jessica L. Crance.Differences in acoustic features of vocalizations produced by killer whales cross-socialized with bottlenose dolphins. The Journal of the Acoustical Society of America, 2014 DOI: 10.1121/1.4893906
19:00 30 September 2014 by Catherine Brahic
Three years ago, an adult chimpanzee called Nick dipped a piece of moss into a watering hole in Uganda’s Budongo Forest. Watched by a female, Nambi, he lifted the moss to his mouth and squeezed the water out. Nambi copied him and, over the next six days, moss sponging began to spread through the community. A chimp trend was born.
Until that day in November 2011, chimps had only been seen to copy actions in controlled experiments, and social learning had never been directly observed in the wild.
To prove that Nambi and the seven other chimps who started using moss sponges didn’t just come up with the idea independently, Catherine Hobaiter of the University of St Andrews, UK, and her colleagues used their own innovation: a statistical analysis of the community’s social network. They were able to track how moss-sponging spread and calculated that once a chimp had seen another use a moss sponge, it was 15 times more likely to do so itself.
A decade ago it was believed that only humans have the capacity to imitate, says Frans de Waal of Emory University in Atlanta, Georgia. “The present study is the first on apes to show by means of networking analysis that habits travel along paths of close relationships,” he says, adding that a similar idea was shown not long ago for humpback whale hunting techniques.
Caught in the act
Copying may seem like the easiest thing to us, but not all animals are able. Chimps at the Gombe Stream reserve in Tanzania can copy each other using twigs to fish out termites, but the baboons that watch them haven’t picked up the trick. “They don’t get it,” says Andrew Whiten of the University of St Andrews.
Whiten previously listed 39 behaviours that were found only in some communities of chimps, suggesting these were picked up from other group members rather than being innate behaviours. Since then, more have been added, but they still number in the dozens, not the thousands.
Given how rarely chimps pick up trends, it’s exciting that someone was on hand to watch it happen in this latest study, says Whiten.
Ultimately, he says, our ability to both invent and copy meant our ancestors could exploit a cognitive niche. “They began hunting large game by doing it the brainy way.” Imitation, it turns out, is not just the sincerest form of flattery, it’s also a smart thing to do.
Journal reference: PLoS Biology, DOI: 10.1371/journal.pbio.1001960
Date: September 29, 2014
Source: Springer Science+Business Media
Add dolphins to the list of magnetosensitive animals, French researchers say. Dolphins are indeed sensitive to magnetic stimuli, as they behave differently when swimming near magnetized objects. So says Dorothee Kremers and her colleagues at Ethos unit of the Université de Rennes in France, in a study in Springer’s journalNaturwissenschaften — The Science of Nature. Their research, conducted in the delphinarium of Planète Sauvage in France, provides experimental behavioral proof that these marine animals are magnetoreceptive.
Magnetoreception implies the ability to perceive a magnetic field. It is supposed to play an important role in how some land and aquatic species orientate and navigate themselves. Some observations of the migration routes of free-ranging cetaceans, such as whales, dolphins and porpoises, and their stranding sites suggested that they may also be sensitive to geomagnetic fields.
Because experimental evidence in this regard has been lacking, Kremers and her colleagues set out to study the behavior of six bottlenose dolphins in the delphinarium of Planète Sauvage in Port-Saint-Père. This outdoor facility consists of four pools, covering 2,000 m² of water surface. They watched the animals’ spontaneous reaction to a barrel containing a strongly magnetized block or a demagnetized one. Except from this characteristic, the blocks were identical in form and density. The barrels were therefore indistinguishable as far as echolocation was concerned, the method by which dolphins locate objects by bouncing sound waves off them.
During the experimental sessions, the animals were free to swim in and out of the pool where the barrel was installed. All six dolphins were studied simultaneously, while all group members were free to interact at any time with the barrel during a given session. The person who was assigned the job to place the barrels in the pools did not know whether it was magnetized or not. This was also true for the person who analyzed the videos showing how the various dolphins reacted to the barrels.
The analyses of Ethos team revealed that the dolphins approached the barrel much faster when it contained a strongly magnetized block than when it contained a similar not magnetized one. However, the dolphins did not interact with both types of barrels differently. They may therefore have been more intrigued than physically drawn to the barrel with the magnetized block.
“Dolphins are able to discriminate between objects based on their magnetic properties, which is a prerequisite for magnetoreception-based navigation,” says Kremers. “Our results provide new, experimentally obtained evidence that cetaceans have a magenetic sense, and should therefore be added to the list of magnetosensitive species.”
- Dorothee Kremers, Juliana López Marulanda, Martine Hausberger, Alban Lemasson. Behavioural evidence of magnetoreception in dolphins: detection of experimental magnetic fields. Naturwissenschaften, 2014 DOI:10.1007/s00114-014-1231-x
Date: September 18, 2014
Source: University of Sydney
Dogs generally seem to be cheerful, happy-go-lucky characters, so you might expect that most would have an optimistic outlook on life.
In fact some dogs are distinctly more pessimistic than others, research from the University of Sydney shows.
“This research is exciting because it measures positive and negative emotional states in dogs objectively and non-invasively. It offers researchers and dog owners an insight into the outlook of dogs and how that changes,” said Dr Melissa Starling, from the Faculty of Veterinary Science. Her PhD research findings are published in PLOS One today.
“Finding out as accurately as possible whether a particular dog is optimistic or pessimistic is particularly helpful in the context of working and service dogs and has important implications for animal welfare.”
Dogs were taught to associate two different sounds (two octaves apart) with whether they would get the preferred reward of milk or instead get the same amount of water. Once the dogs have learnt the discrimination task, they are presented with ‘ambiguous’ tones.
If dogs respond after ambiguous tones, it shows that they expect good things will happen to them, and they are called optimistic. They can show how optimistic they are by which tones they respond to. A very optimistic dog may even respond to tones that sound more like those played before water is offered.
“Of the dogs we tested we found more were optimistic than pessimistic but it is too early to say if that is true of the general dog population,” said Dr Starling.
However it does mean that both individuals and institutions (kennels, dog minders) can have a much more accurate insight into the emotional make-up of their dogs.
According to the research a dog with an optimistic personality expects more good things to happen, and less bad things. She will take risks and gain access to rewards. She is a dog that picks herself up when things don’t go her way, and tries again. Minor setbacks don’t bother her.
If your dog has a pessimistic personality, he expects less good things to happen and more bad things. This may make him cautious and risk averse. He may readily give up when things don’t go his way, because minor setbacks distress him. He may not be unhappy per se, but he is likely to be most content with the status quo and need some encouragement to try new things.
“Pessimistic dogs appeared to be much more stressed by failing a task than optimistic dogs. They would whine and pace and avoid repeating the task while the optimistic dogs would appear unfazed and continue,” said Dr Starling.
“This research could help working dog trainers select dogs best suited to working roles. If we knew how optimistic or pessimistic the best candidates for a working role are, we could test dogs’ optimism early and identify good candidates for training for that role. A pessimistic dog that avoids risks would be better as a guide dog while an optimistic, persistent dog would be more suited to detecting drugs or explosives.”
Dr Starling has been working with Assistance Dogs Australia, a charity organisation that provides service and companion dogs to people with disabilities, to investigate whether an optimism measure could aid in selecting suitable candidates for training.
The research not only suggests how personality may affect the way dogs see the world and how they behave but how positive or negative their current mood is.
“This research has the potential to completely remodel how animal welfare is assessed. If we know how optimistic or pessimistic an animal usually is, it’s possible to track changes in that optimism that will indicate when it is in a more positive or negative emotional state than usual,” said Dr Starling.
“The remarkable power of this is the opportunity to essentially ask a dog ‘How are you feeling?’ and get an answer. It could be used to monitor their welfare in any environment, to assess how effective enrichment activities might be in improving welfare, and pinpoint exactly what a dog finds emotionally distressing.”
- Melissa J. Starling, Nicholas Branson, Denis Cody, Timothy R. Starling, Paul D. McGreevy. Canine Sense and Sensibility: Tipping Points and Response Latency Variability as an Optimism Index in a Canine Judgement Bias Assessment. PLoS ONE, 2014; 9 (9): e107794 DOI:10.1371/journal.pone.0107794
Victor-M Amela, Ima Sanchís, Lluís Amiguet
“Las plantas tienen neuronas, son seres inteligentes”
29/12/2010 – 02:03
Foto: KIM MANRESA
Gracias a nuestros amigos de Redes, el programa de Eduard Punset, buscadores incansables de todo conocimiento científico que amplíe los límites del saber, de quiénes somos y qué papel desempeñamos en esta sopa de universos, descubrimos a Mancuso, que nos explica que las plantas, vistas a cámara rápida, se comportan como si tuvieran cerebro: tienen neuronas, se comunican mediante señales químicas, toman decisiones, son altruistas y manipuladoras. ¿Hace cinco años era imposible hablar de comportamiento de las plantas, hoy podemos empezar a hablar de su inteligencia¿… Puede que pronto empecemos a hablar de sus sentimientos. Mancuso estará en Redes el próximo día 2. No se lo pierdan.
Las plantas son organismos inteligentes, pero se mueven y toman decisiones en un tiempo más largo que el del hombre.
Hoy sabemos que tienen familia y parientes y que reconocen su cercanía. Se comportan de manera totalmente distinta si a su lado hay parientes o hay extraños. Si son parientes no compiten: a través de las raíces, dividen el territorio de manera equitativa.
¿Un árbol puede voluntariamente mandar savia a una planta pequeña?
Sí. Las plantas requieren luz para vivir, ypara que una semilla llegue a la luz deben pasar muchos años; mientras tanto, son nutridas por árboles de su misma especie.
Los cuidados parentales sólo se dan en animales muy evolucionados y es increíble que se den en las plantas.
Entonces, se comunican.
Sí, en una selva todas las plantas están en comunicación subterránea a través de las raíces. Y también fabrican moléculas volátiles que avisan a plantas lejanas sobre lo que está sucediendo.
Cuando una planta es atacada por un patógeno, inmediatamente produce moléculas volátiles que pueden viajar kilómetros, y que avisan a todas las demás para que preparen sus defensas.
Producen moléculas químicas que las convierten en indigeribles, y pueden ser muy agresivas. Hace diez años, en Botsuana introdujeron en un gran parque 200.000 antílopes, que comenzaron a comerse las acacias con intensidad. Tras pocas semanas muchos murieron y al cabo de seis meses murieron más de 10.000, y no advertían por qué. Hoy sabemos que fueron las plantas.
Sí, y las plantas aumentaron hasta tal punto la concentración de taninos en sus hojas, que se convirtieron en un veneno.
¿Las plantas también son empáticas con otros seres?
Es difícil decirlo, pero hay una cosa segura: las plantas pueden manipular a los animales. Durante la polinización producen néctar y otras sustancias para atraer a los insectos. Las orquídeas producen flores que son muy similares a las hembras de algunos insectos, que, engañados, acuden a ellas. Y hay quien afirma que hasta el ser humano es manipulado por las plantas.
Todas las drogas que usa el hombre (café, tabaco, opio, marihuana…) derivan de las plantas, ¿pero por qué las plantas producen una sustancia que convierte a humanos en dependientes? Porque así las propagamos. Las plantas utilizan al hombre como transporte. Hay investigaciones sobre ello.
Si mañana desaparecieran las plantas del planeta, en un mes toda la vida se extinguiría porque no habría comida ni oxígeno. Todo el oxígeno que respiramos viene de ellas. Pero si nosotros desapareciéramos, no pasaría nada. Somos dependientes de las plantas, pero las plantas no lo son de nosotros. Quien es dependiente está en una situación inferior, ¿no?
Las plantas son mucho más sensibles. Cuando algo cambia en el ambiente, como ellas no pueden escapar, han de ser capaces de sentir con mucha anticipación cualquier mínimo cambio para adaptarse.
¿Y cómo perciben?
Cada punta de raíz es capaz de percibir continuamente y a la vez como mínimo quince parámetros distintos físicos y químicos (temperatura, luz, gravedad, presencia de nutrientes, oxígeno).
Es su gran descubrimiento, y es suyo.
En cada punta de las raíces existen células similares a nuestras neuronas y su función es la misma: comunicar señales mediante impulsos eléctricos, igual que nuestro cerebro. En una planta puede haber millones de puntas de raíces, cada una con su pequeña comunidad de células; y trabajan en red como internet.
Ha encontrado el cerebro vegetal.
Sí, su zona de cálculo. La cuestión es cómo medir su inteligencia. Pero de una cosa estamos seguros: son muy inteligentes, su poder de resolver problemas, de adaptación, es grande. Hoy sobre el planeta el 99,6% de todo lo que está vivo son plantas.
… Y sólo conocemos el 10%.
Y en ese porcentaje tenemos todo nuestro alimento y la medicina. ¿Qué habrá en el restante 90%?… A diario, cientos de especies vegetales desconocidas se extinguen. Tal vez poseían la capacidad de una cura importante, no lo sabremos nunca. Debemos proteger las plantas por nuestra supervivencia.
¿Qué le emociona de las plantas?
Algunos comportamientos son muy emocionantes. Todas las plantas duermen, se despiertan, buscan la luz con sus hojas; tienen una actividad similar a la de los animales. Filmé el crecimiento de unos girasoles, y se ve clarísimo cómo juegan entre ellos.
Sí, establecen el comportamiento típico del juego que se ve en tantos animales. Cogimos una de esas pequeñas plantas y la hicimos crecer sola. De adulta tenía problemas de comportamiento: le costaba girar en busca del sol, le faltaba el aprendizaje a través del juego. Ver estas cosas es emocionante.
Date: July 28, 2014
Source: University of Michigan Health System
Summary: Babies can learn what to fear in the first days of life just by smelling the odor of their distressed mothers’, new research suggests. And not just “natural” fears: If a mother experienced something before pregnancy that made her fear something specific, her baby will quickly learn to fear it too — through her odor when she feels fear.
Babies can learn what to fear in the first days of life just by smelling the odor of their distressed mothers, new research suggests. And not just “natural” fears: If a mother experienced something before pregnancy that made her fear something specific, her baby will quickly learn to fear it too — through the odor she gives off when she feels fear.
In the first direct observation of this kind of fear transmission, a team of University of Michigan Medical School and New York University studied mother rats who had learned to fear the smell of peppermint — and showed how they “taught” this fear to their babies in their first days of life through their alarm odor released during distress.
In a new paper in the Proceedings of the National Academy of Sciences, the team reports how they pinpointed the specific area of the brain where this fear transmission takes root in the earliest days of life.
Their findings in animals may help explain a phenomenon that has puzzled mental health experts for generations: how a mother’s traumatic experience can affect her children in profound ways, even when it happened long before they were born.
The researchers also hope their work will lead to better understanding of why not all children of traumatized mothers, or of mothers with major phobias, other anxiety disorders or major depression, experience the same effects.
“During the early days of an infant rat’s life, they are immune to learning information about environmental dangers. But if their mother is the source of threat information, we have shown they can learn from her and produce lasting memories,” says Jacek Debiec, M.D., Ph.D., the U-M psychiatrist and neuroscientist who led the research.
“Our research demonstrates that infants can learn from maternal expression of fear, very early in life,” he adds. “Before they can even make their own experiences, they basically acquire their mothers’ experiences. Most importantly, these maternally-transmitted memories are long-lived, whereas other types of infant learning, if not repeated, rapidly perish.”
Peering inside the fearful brain
Debiec, who treats children and mothers with anxiety and other conditions in the U-M Department of Psychiatry, notes that the research on rats allows scientists to see what’s going on inside the brain during fear transmission, in ways they could never do in humans.
He began the research during his fellowship at NYU with Regina Marie Sullivan, Ph.D., senior author of the new paper, and continues it in his new lab at U-M’s Molecular and Behavioral Neuroscience Institute.
The researchers taught female rats to fear the smell of peppermint by exposing them to mild, unpleasant electric shocks while they smelled the scent, before they were pregnant. Then after they gave birth, the team exposed the mothers to just the minty smell, without the shocks, to provoke the fear response. They also used a comparison group of female rats that didn’t fear peppermint.
They exposed the pups of both groups of mothers to the peppermint smell, under many different conditions with and without their mothers present.
Using special brain imaging, and studies of genetic activity in individual brain cells and cortisol in the blood, they zeroed in on a brain structure called the lateral amygdala as the key location for learning fears. During later life, this area is key to detecting and planning response to threats — so it makes sense that it would also be the hub for learning new fears.
But the fact that these fears could be learned in a way that lasted, during a time when the baby rat’s ability to learn any fears directly was naturally suppressed, is what makes the new findings so interesting, says Debiec.
The team even showed that the newborns could learn their mothers’ fears even when the mothers weren’t present. Just the piped-in scent of their mother reacting to the peppermint odor she feared was enough to make them fear the same thing.
And when the researchers gave the baby rats a substance that blocked activity in the amygdala, they failed to learn the fear of peppermint smell from their mothers. This suggests, Debiec says, that there may be ways to intervene to prevent children from learning irrational or harmful fear responses from their mothers, or reduce their impact.
From animals to humans: next steps
The new research builds on what scientists have learned over time about the fear circuitry in the brain, and what can go wrong with it. That work has helped psychiatrists develop new treatments for human patients with phobias and other anxiety disorders — for instance, exposure therapy that helps them overcome fears by gradually confronting the thing or experience that causes their fear.
In much the same way, Debiec hopes that exploring the roots of fear in infancy, and how maternal trauma can affect subsequent generations, could help human patients. While it’s too soon to know if the same odor-based effect happens between human mothers and babies, the role of a mother’s scent in calming human babies has been shown.
Debiec, who hails from Poland, recalls working with the grown children of Holocaust survivors, who experienced nightmares, avoidance instincts and even flashbacks related to traumatic experiences they never had themselves. While they would have learned about the Holocaust from their parents, this deeply ingrained fear suggests something more at work, he says.
Going forward, he hopes to work with U-M researchers to observe human infants and their mothers — including U-M psychiatrist Maria Muzik, M.D. and psychologist Kate Rosenblum, Ph.D., who run a Women and Infants Mental Health clinic and research program and also work with military families. The program is currently seeking women and their children to take part in a range of studies.
- Jacek Debiec and Regina Marie Sullivan. Intergenerational transmission of emotional trauma through amygdala-dependent mother-to-infant transfer of specific fear. PNAS, July 28, 2014 DOI: 10.1073/pnas.1316740111
A team of researchers working in South Africa have a sneaking suspicion that they’re being used as human shields. Monkeys who normally spend their time in trees avoiding predators like leopards and raptors seem to relax their vigilance a little around humans, venturing down to eat.
Humans, as well as human infrastructure, can alter the relationship between predators and prey by shielding one from the other. A stone wall filled with crevices could provide a refuge for a small critter, while a person’s presence might indirectly guard an animal against its would-be killer. Those who are used to us may actually begin to take more risks when we’re around.
To quantify this alteration in risk-taking behavior, Katarzyna Nowak of Durham University and colleagues tested the magnitude of the “human shield effect” on two groups of samango monkeys (Cercopithecus mitis erythrarcus) at a site with high natural predator density and no human hunting pressure.
Samango monkeys spend most of their time in trees avoiding predators on the ground, like large cats, and those in the canopies above, like birds of prey. They don’t stray very far, and they don’t climb too high. When observed by humans, however, the monkeys preferred to climb down to eat food from the forest floor. The work was published in Behavioral Ecology earlier this month.
The researchers set up feeding stations at various levels in the forest and looked at a fear measure known as “giving-up densities.” That’s the density of food remaining in a patch when a forager leaves. (It’s a little like, say, you were in a hurry and didn’t eat your whole burger.) With lots of predators at this site, the giving-up densities were greatest at ground level (0.1 meter) relative to the three tree canopy levels (2.5, 5, and 7.5 meters up). This highlights a strong vertical axis of fear, as they researchers say.
“The amount of food monkeys depleted from buckets over the course of the experiment varied with height, with the most food left uneaten at ground level, where there is a risk of predation by leopards and caracals,” Nowak tells The Independent.
When human followers were present, giving-up densities were reduced at all four heights. In one of the groups, the vertical axis totally disappeared in the presence of human observers. By passively keeping terrestrial predators away from the area, we seem to lower the monkeys’ perceived risks.
“When a human observer was following monkeys, they ate more food at every height, with the most notable differences at the bottom two levels,” Nowak explains. “Animals are expected to deplete more food where and when they feel safe [but] we had not expected human followers to have such strong effect!”
Date: June 26, 2014
Summary: While preferring silence to music from the West, chimpanzees apparently like to listen to the different rhythms of music from Africa and India, according to new research published by the American Psychological Association.
While preferring silence to music from the West, chimpanzees apparently like to listen to the different rhythms of music from Africa and India, according to new research published by the American Psychological Association.
“Our objective was not to find a preference for different cultures’ music. We used cultural music from Africa, India and Japan to pinpoint specific acoustic properties,” said study coauthor Frans de Waal, PhD, of Emory University. “Past research has focused only on Western music and has not addressed the very different acoustic features of non-Western music. While nonhuman primates have previously indicated a preference among music choices, they have consistently chosen silence over the types of music previously tested.”
Previous research has found that some nonhuman primates prefer slower tempos, but the current findings may be the first to show that they display a preference for particular rhythmic patterns, according to the study. “Although Western music, such as pop, blues and classical, sound different to the casual listener, they all follow the same musical and acoustic patterns. Therefore, by testing only different Western music, previous research has essentially replicated itself,” the authors wrote. The study was published in APA’s Journal of Experimental Psychology: Animal Learning and Cognition.
When African and Indian music was played near their large outdoor enclosures, the chimps spent significantly more time in areas where they could best hear the music. When Japanese music was played, they were more likely to be found in spots where it was more difficult or impossible to hear the music. The African and Indian music in the experiment had extreme ratios of strong to weak beats, whereas the Japanese music had regular strong beats, which is also typical of Western music.
“Chimpanzees may perceive the strong, predictable rhythmic patterns as threatening, as chimpanzee dominance displays commonly incorporate repeated rhythmic sounds such as stomping, clapping and banging objects,” said de Waal.
Sixteen adult chimps in two groups participated in the experiment at the Yerkes National Primate Research Center at Emory University. Over 12 consecutive days for 40 minutes each morning, the groups were given the opportunity to listen to African, Indian or Japanese music playing on a portable stereo near their outdoor enclosure. Another portable stereo not playing any music was located at a different spot near the enclosure to rule out behavior that might be associated with an object rather than the music. The different types of music were at the same volume but played in random order. Each day, researchers observed the chimps and recorded their location every two minutes with handwritten notes. They also videotaped the activity in the enclosure. The chimps’ behavior when the music was played was compared to their behavior with no music.
“Chimpanzees displaying a preference for music over silence is compelling evidence that our shared evolutionary histories may include favoring sounds outside of both humans’ and chimpanzees’ immediate survival cues,” said lead author Morgan Mingle, BA, of Emory and Southwestern University in Austin. “Our study highlights the importance of sampling across the gamut of human music to potentially identify features that could have a shared evolutionary root.”
- Morgan E. Mingle, Timothy M. Eppley, Matthew W. Campbell, Katie Hall, Victoria Horner, Frans B. M. de Waal. Chimpanzees Prefer African and Indian Music Over Silence.. Journal of Experimental Psychology: Animal Learning and Cognition, 2014; DOI: 10.1037/xan0000032
It was love at first pet when Laurel Braitman and her husband adopted a 4-year-old Bernese mountain dog, a 120-pound bundle of fur named Oliver.
The first few months were blissful. But over time, Oliver’s troubled mind slowly began to reveal itself. He snapped at invisible flies. He licked his tail until it was wounded and raw. He fell to pieces when he spied a suitcase. And once, while home alone, he ripped a hole in a screen and jumped out of a fourth-floor window. To everyone’s astonishment, he survived.
Oliver’s anguish devastated Dr. Braitman, a historian of science, but it also awakened her curiosity and sent her on an investigation deep into the minds of animals. The result is the lovely, big-hearted book “Animal Madness,” in which Dr. Braitman makes a compelling case that nonhuman creatures can also be afflicted with mental illness and that their suffering is not so different from our own.
In the 17th century, Descartes described animals as automatons, a view that held sway for centuries. Today, however, a large and growing body of research makes it clear that animals have never been unthinking machines.
We now know that species from magpies to elephants can recognize themselves in the mirror, which some scientists consider a sign of self-awareness. Rats emit a form of laughter when they’re tickled. And dolphins, parrots and dogs show clear signs of distress when their companions die. Together, these and many other findings demonstrate what any devoted pet owner has probably already concluded: that animals have complex minds and rich emotional lives.
Unfortunately, as Dr. Braitman notes, “every animal with a mind has the capacity to lose hold of it from time to time.”
Take Gigi, a female gorilla who developed what looked like panic attacks after being terrorized by a younger male. Whenever she saw her tormentor, she “seemed to shut down, rocking and trembling,” Dr. Braitman writes. Many other beasts round out the miserable menagerie, including Sunita, a tiger with stress-induced facial tics; Charlie, a macaw who plucked out all her feathers; and Gus, a polar bear who swam endless figure eights — for as many as 12 hours a day — in his pool at the Central Park Zoo.
Dr. Braitman and the experts she consults are careful about how they interpret this behavior. For example, although a dog’s nonstop tail-licking may resemble the endless hand-washing of a human with obsessive-compulsive disorder, one veterinary behaviorist points out that because she cannot prove that dogs are having obsessive thoughts, she prefers a diagnosis of “compulsive disorder” instead.
Still, it’s clear that the animals are suffering, and the triggers are often the same sorts of stress and trauma that can cause breakdowns in humans: a natural disaster, abuse, the loss of a loved one. And we’re not the only species that bears the burden of war; some of the military dogs that served in Iraq and Afghanistan display the same PTSD-like symptoms that afflict their human colleagues.
Dr. Braitman does not shy away from controversial topics — most notably, the question of whether animals can commit suicide. Charlie, the feather-plucking macaw, died when she fell out of a tree and onto a metal stake in the ground, prompting her owner to wonder if the bird had deliberately brought about her own demise. “Suicide” is a loaded word, and Charlie’s story is unconvincing, but animals can certainly engage in self-harming behaviors, from repeatedly banging their heads against walls to simply refusing to eat.
Animals “may have fewer tools available to them to inflict mortal wounds and also lack humanity’s sophisticated cognitive abilities to plan their own ends, but they can and do harm themselves,” Dr. Braitman writes. “Sometimes they die.”
Throughout the book, she argues that anthropomorphism — or the assignment of human traits to other species — can serve a useful purpose, especially if we “anthropomorphize well.” She writes, “Instead of self-centered projection, anthropomorphism can be a recognition of bits and pieces of our human selves in other animals and vice versa.”
Though we may never know for sure what parrots or polar bears are feeling, “making educated guesses about animal emotions” is often the first step in alleviating their pain. Healing troubled animal minds is now a bona fide industry, populated with dog behaviorists, cat whisperers, elephant monks and horse massagers.
For some animals, behavioral therapy, environmental enrichment or companionship is enough to ease the agony. Others may need a pharmaceutical assist — from Prozac, Valium, Thorazine or one of the many psychiatric drugs now available to creatures throughout the animal kingdom.
“Prozac Nation has been offering citizenship to nonhumans for decades,” Dr. Braitman writes. Gigi, the terrorized gorilla, received a round of Xanax and Paxil and eventually recovered (mostly) with the help of a psychiatrist and a zookeeper who never gave up on her.
Though humans are a leading cause of animal unhappiness — captivity alone causes many problems, even in the absence of outright neglect or abuse — “Animal Madness” is also brimming with compassion and the tales of the many, many humans who devote their days to making animals well.
Ministry spokesman Ultimo Valadares said the government is working out the details of a five-year moratorium on fishing of the species called piracatinga that is expected to go into effect early next year.
“That should give us enough time to find an alternative bait for the piracatinga,” Valadares said by phone.
Nivia do Campo, president of an environmental activist group in the northern jungle state of Amazonas, welcomed the news because more than 1,500 freshwater dolphins are killed annually in the Mamiraua Reserve where she studies the mammals.
She said that since 2000, when fishermen started slaughtering them for bait, the number of dolphins living on the reserve has been dropping by about 10 percent a year. The reserve currently has a population of about 13,000 dolphins.
Poor fishermen are encouraged to use dolphin flesh as bait by merchants from neighboring Colombia, a big market for that species, de Campo said.
Known as the “water vulture” because it thrives on decomposing matter in rivers, the piracatinga is not consumed by people living along the rivers of the Amazon region.
The pink dolphin is under threat, “and if nothing is done to stop the killing it will become extinct,” de Campo added. “That is why the moratorium is excellent news. It will allow us to discover other baits fishermen can and continue earning money selling piracatinga she said.
The moratorium will also help stop the killing of the Amazon caiman, whose flesh is also used as bait to catch piracatinga.
For centuries, the pink dolphins have been revered by locals and protected by myth. According to one tale, the dolphins transform into handsome men and leave the water at night, seducing local women before returning to the river. Many consider it bad luck to kill them.
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