A Tasmanian devil with devil facial tumor disease (DFTD)
When amateur nature photographer Christo Baars settled into his hunting blind (a cover device) in the Tasmanian bush in 1996, there was no reason for him to expect anything out of the ordinary. Baars had visited the site in Mount William National Park a few times, and it was a good place to photograph Tasmanian devils – close relatives of the now extinct Tasmanian tiger. Tasmanian devils are nocturnal animals, and based on his previous expeditions, Baars expected to see 10 a night, minimum.
A characteristic Tasmanian devil ‘yawn’
But Baars didn’t see a single Tasmanian devil during his first night in the blind and saw barely any the following night. This was the first indication that something might be wrong. The first sign of a serious problem, however, was when Baars spotted a Tasmanian devil with a weird disfigurement on its face: a strange, lumpy, tumor-like growth.
The photographs Baars took of the afflicted animal in early 1996 are the first known recordings of a disease now termed devil facial tumor disease (DFTD). As of January 2013, the disease has killed 80 percent of the Australian island’s Tasmanian devil population. Will Tasmanian devils thus become the latest in a long list of extinct animals?
Two young Tasmanian devils
Before we explore the terrible disease affecting them, let’s take a look at the peculiar marsupials themselves. Over the years, Tasmanian devils have acquired a bad reputation, and much of it is undeserved. That said, they do have some habits humans find less than endearing. For one, they stink – although only when stressed. What’s more, they eat just about anything, from baby animals, to domestic pets, to any kind of carcass they come across – including human corpses and buried horses!
Tasmanian devils have even been known to chew the legs off live sheep. And when scavenging a large carcass, these voracious marsupials like to first eat the soft organs, before snuggling down in the body cavity to enjoy the rest of their feast at leisure.
A close look at those strong jaws
Much like the famous Looney Tunes character, real Tasmanian devils are quick to fly into what looks like a rage. When threatened, they make blood-curdling growls and screeches, lunge at their opponents, and bare their teeth. However, researchers now say that much of this aggressive posturing is performed to avoid fighting. Still, displays like this earned the creatures the name “devil” from early European immigrants.
Male Tasmanian devils often duel, particularly during mating season, and it’s common for adult males to have scars from past battles. They may only weigh up to 26 pounds, but these animals have a ferocious bite – ounce for ounce, the strongest of any predatory land mammal. Sadly, as we’ll see later, this habit of individuals biting one another is partly responsible for the serious predicament in which the species finds itself today.
Baby Tasmanian devils lounging in the sun
In the past, Tasmanian devils, like Tasmanian tigers (otherwise known as thylacines), were blamed for killing livestock in their native island state. People even thought they would attack and eat humans. In truth, though, these predatory marsupials only ever took chickens, or at most livestock weakened by illness. According to modern researchers, Tasmanian devils are nowhere near as vicious as they’ve been portrayed to be. In fact, they’re actually quite shy and nervous around people.
Be that as it may, starting in 1830, Tasmanian devils were trapped and poisoned for a century. Moreover, it was just in the nick of time that the animals were brought back from the brink of extinction – unlike the thylacine. Tasmanian devils were declared protected in 1941, five years after the death of the last thylacine at Hobart Zoo. Yet this still wasn’t the end of the Tasmanian devil being hunted, and culling increased again in the 1950s and ‘60s.
Two Tasmanian devils cuddling up at the Tasmanian Devil Conservation Park in Taranna
The Tasmanian devil has faced numerous threats over the years. Indeed, around 3,000 years ago they went extinct on mainland Australia. (A single tooth has, however, been found and dated to around 430 years ago, but this is disputed.) It’s thought that the carnivorous marsupials couldn't compete with the newly introduced dingoes, although climate change at the time may have also been partly responsible.
These days, Tasmanian devils are only found in the wild on Tasmania. And the combination of their dark coloring (which makes them hard to spot) and partiality for scavenging road kill means that a lot of them end up dying on the road.
Healthy Tasmanian devil
In the future, Tasmanian devils may also face the threat of illegally introduced red foxes, which would compete with the devils for food and dens and also feed on their young. Fortunately, red fox numbers are not yet high enough to have a significant impact. In fact, Tasmanian devils are considered important predators of these introduced pests. Dogs have taken their toll on devil numbers as well – but none of these threats compare to DFTD.
Time for a rest
Returning to the story, after Baars’ discovery, it still took a while for the disease to be properly identified. At first, scientists thought the lumps might be the product of a virus that triggers lymphatic cancer. Further investigation, however, showed that the tumors did not seem to be virus-related. The evidence began pointing to a contagious type of cancer – a frightening possibility and one that turned out to be true.
A Tasmanian devil with a DFTD mouth tumor
This rare disease is one of only three known contagious cancers in the world; one of the others affects dogs, while the other affects Syrian hamsters. In the Tasmanian devil’s case, the infection is, as suggested, spread through bites. When a diseased devil bites a healthy one, the cancer cells are passed on into the wound, infecting the bitten animal.
Then, once the tumors start to grow, the unfortunate marsupial has only a few months left to live – and infect other Tasmanian devils. The growing tumors affect a diseased devil’s jaw and teeth and obstruct its ability to feed, eventually causing it to starve to death. It’s an awful, painful and lingering way to die, and currently there is no cure.
A Tasmanian devil with advanced tumors
It’s thought that the disease takes hold so easily because Tasmanian devils are all so genetically close to one another. Also, the cancer itself has such similar DNA to the devils’ that their immune systems don’t recognize the cancer cells as alien. The disease itself is thought to have originated in a single individual Tasmanian devil about two decades ago and then spread from there.
One of the impacts of the disease is that Tasmanian devils are now breeding earlier, which is presumed to be a result of their shortened lifespan. These days, female devils frequently die soon after giving birth to their first litter.
Field workers monitor Tasmanian devils in the wild.
The battle against DFTD is a difficult one. Wild Tasmanian devils, officially labeled endangered since 2008, are carefully monitored for signs of the disease, and infected animals are captured and euthanized immediately. Still, conservationists seem powerless as the disease continues to sweep the island. A vaccine cannot be developed without sufficient funds, and even if there were one, the logistics of inoculating the entire wild population would make curing the disease almost impossible.
Instead, scientists are concentrating on keeping small, uninfected captive populations going. Some Tasmanian devils have been sent to reserves in mainland Australia for breeding, while others are kept in isolated locations in Tasmania. The idea is to reintroduce this backup population into the wild in the future, if necessary.
A Tasmanian devil in its natural environment
Recently, it seemed as if there might be some hope for the wild Tasmanian devils. A population of devils untouched by the disease was discovered in the northwest of the island. Genetically, these Tasmanian devils were found to be slightly different, and the theory was that perhaps this difference would be enough to make some of them naturally resistant to DFTD.
Unfortunately, saving the Tasmanian devil is not a priority for everyone. Recently, it was announced that a mine close to Temma in the northwest region of Tarkine has been approved. This was controversial, because the area is one of the last remaining natural devil habitats in Tasmania and has also been put forward as a prospective World Heritage site. Now, those trying to preserve the Tasmanian devils fear not only the mine’s impact direct on the environment, but the heavy traffic it will bring as well.
How could anyone want to harm these little guys?
It would be extremely tragic if the Tasmanian devil succumbed to human greed and went the way of the Tasmanian tiger. The Save the Tasmanian Devil Program continues the fight to keep these unique marsupials in the wild. For more information about the program, Tasmanian devils and DFTD, and to donate and see what you can do to help, please visit tassiedevil.com.au.