The fruit body ranges in shape from pear-like with a flattened top, to nearly spherical, and reaches dimensions of 1.5 to 6 cm (5⁄8 to 2+3⁄8 in) wide by 3 to 7 cm (1+1⁄8 to 2+3⁄4 in) tall. It has a stem-like base, and is whitish before browning in age. The outer surface of the fruit body (the exoperidium) is covered in short cone-shaped spines that are interspersed with granular warts. The spines, which are whitish, gray, or brown, can be easily rubbed off, and leave reticulate pock marks or scars after they are removed. The base of the puffball is thick, and has internal chambers. It is initially white, but turns yellow, olive, or brownish in age. The reticulate pattern resulting from the rubbed-off spines is less evident on the base.
In maturity, the exoperidium at the top of the puffball sloughs away, revealing a pre-formed hole (ostiole) in the endoperidium, through which the spores can escape. In young puffballs, the internal contents, the gleba, is white and firm, but turns brown and powdery as the spores mature.  The gleba contains minute chambers that are lined with hymenium (the fertile, spore-bearing tissue); the chambers collapse when the spores mature. Mature puffballs release their powdery spores through the ostiole when they are compressed by touch or falling raindrops. A study of the spore release mechanism in L. pyriforme using high-speed schlieren photography determined that raindrops of 1 mm diameter or greater, including rain drips from nearby trees, were sufficient to cause spore discharge. The puffed spores are ejected from the ostiole at a velocity of about 100 cm/second to form a centimeter-tall cloud one-hundredth of a second after impact. A single puff like this can release over a million spores.
The spores are spherical, thick-walled, covered with minute spines, and measure 3.5–4.5 μm in diameter. The capillitia (threadlike filaments in the gleba in which spores are embedded) are yellow-brown to brownish in color, lack septae, and measure 3–7.5 μm in diameter. The basidia (spore-bearing cells) are club-shaped, four-spored, and measure 7–9 by 4–5 μm. The basidia bear four slender sterigmata of unequal length ranging from 5–10 μm long. The surface spines are made of chains of pseudoparenchymatous hyphae (resembling the parenchyma  of higher plants), in which the individual hyphal cells are spherical to elliptical in shape, thick-walled (up to 1 μm), and measure 13–40 by 9–35 μm. These hyphae do not have clamp connections.


Most western terrestrial garter snakes have a yellow, light orange, or white dorsal stripe, accompanied by two stripes of the same color, one on each side. Some varieties have red or black spots between the dorsal stripe and the side stripes. It is an immensely variable species, and even the most experienced herpetologists have trouble when it comes to identification. They are medium-sized snakes, usually 46–104 cm (18–41 in).
Like many species of North American garter snake, the western terrestrial garter snake possesses a mildly venomous saliva. Specimens collected from Idaho and Washington produced venom with myonecrotic (muscle tissue-killing) effects when injected into the gastrocnemius muscles of mice. Several cases of mild human envenomation with local edema and other symptoms (but without any systemic symptoms) have occurred from the wandering garter snake subspecies, including in Colorado.
This species is the only garter snake species with a well-documented tendency to constrict prey, although the constriction is inefficient when compared with the constriction of many other snakes (such as the gopher snake), involving disorganized, loose, and sometimes unstable coils and a longer time required to kill prey. Snakes from Colorado populations of terrestrial garter snakes appear to be more efficient at killing their prey by constriction than those from Pacific Coast populations.


The diet of Thamnophis elegans relies heavily on the prey available in the environment, and thus varies due to geographical differences. This makes the western terrestrial garter snake an excellent example of polyphagism. There are two main variants that are most prevalent: coastal and inland. Since coastal  T. elegans is found along the West Coast of the United States, it is found near the coast of the Pacific Ocean. On the other hand, if the snake population is considered to be inland, it is found near inland water sources such as streams, ponds, or lakes.
Coastal populations' food sources mainly include terrestrial prey such as slugs, salamanders, small mammals, and lizards. In contrast, inland populations indulge in a semi-aquatic diet containing frog and toad larvae, leeches, and fish. Thus, aquatic food sources are a staple in the inland snake populations' diet.
Coastal snakes are less likely to respond to chemical cues received from fish, which can be inferred by less rapid tongue-flicking when around them. They are also less likely to attack and ingest fish. This preference in diet is so strong that the snake will starve before eating non-preferred prey types. Further, this appears to be genetically determined as this variation in diet is observed in newborn snakes from both populations.
When hunting, the Western Garter Snake's actions are chemically and visually mediated on land and in water. Regardless the habitat in which foraging takes place, both ecotypes utilize similar techniques. This consists of attacks that are both aerial and underwater. These include craning, cruising, and diving. However, coastal snakes are less likely to participate these activities.
These differences in diet and foraging behavior between coastal and inland snake populations suggest that the species has undergone microevolution. Due to dietary and foraging differences between variants of T. elegans, it can be inferred that coastal populations have filled a niche in the environment that allows them to no longer rely on fish as a major food source.


Thamnophis elegans is found in central British Columbia, central Alberta, and southwestern Manitoba in Canada. It can be found in the western United States, as far east as western Nebraska and the Oklahoma Panhandle. An isolated population occurs in Baja California, Mexico.


Thamnophis elegans occurs in a wide variety of habitats, including grasslands, woodlands, and coniferous forests, from sea level up to 3,962 m (12,999 ft). It is primarily terrestrial, although populations in the Great Basin and Rocky Mountains are semi-aquatic.


Amanita bisporigera is a deadly poisonous species of fungus in the family Amanitaceae. It is commonly known as the eastern destroying angel amanita, the eastern North American destroying angel or just as the destroying angel, although the fungus shares this latter name with three other lethal white Amanita species, A. ocreata, A. verna and A. virosa. The fruit bodies are found on the ground in mixed coniferous and deciduous forests of eastern North America south to Mexico, but are rare in western North America; the fungus has also been found in pine plantations in Colombia. The mushroom has a smooth white cap that can reach up to 10 cm (4 in) across, and a stipe, up to 14 cm (5.5 in) long by 1.8 cm (0.7 in) thick, that has a delicate white skirt-like ring near the top. The bulbous stipe base is covered with a membranous sac-like volva. The white gills are free from attachment to the stalk and crowded closely together. As the species name suggests, A. bisporigera typically bears two spores on the basidia, although this characteristic is not as immutable as was once thought.
Amanita bisporigera was described as a new species in 1906. It is classified in the section Phalloideae of the genus Amanita together with other amatoxin-containing species. Amatoxins are cyclic peptides which inhibit the enzyme RNA polymerase II and interfere with various cellular functions. The first symptoms of poisoning appear 6 to 24 hours after consumption, followed by a period of apparent improvement, then by symptoms of liver and kidney failure, and death after four days or more. Amanita bisporigera closely resembles a few other white amanitas, including the equally deadly A. virosa and A. verna. These species, difficult to distinguish from A. bisporigera based on visible field characteristics, do not have two-spored basidia, and do not stain yellow when a dilute solution of potassium hydroxide is applied. The DNA of A. bisporigera has been partially sequenced, and the genes responsible for the production of amatoxins have been determined.


Like most other Amanita species, A. bisporigera is thought to form mycorrhizal relationships with trees. This is a mutually beneficial relationship where the hyphae of the fungus grow around the roots of trees, enabling the fungus to receive moisture, protection and nutritive byproducts of the tree, and giving the tree greater access to soil nutrients. Fruit bodies of Amanita bisporigera are found on the ground growing either solitarily, scattered, or in groups in mixed coniferous and deciduous forests; they tend to appear during summer and early fall. The fruit bodies are commonly found near oak, but have been reported in birch-aspen areas in the west. It is most commonly found in eastern North America, and rare in western North America. It is widely distributed in Canada, and its range extends south to Mexico. The species has also been found in Colombia, where it may have been introduced from trees exported for use in pine plantations.


The color and general appearance of A. bisporigera are similar to those of A. verna and A. virosa. A. bisporigera is at times smaller and more slender than either A. verna or A. virosa, but it varies considerably in size; therefore size is not a reliable diagnostic characteristic. A. virosa fruits in autumn—later than A. bisporigera. A. elliptosperma is less common but widely distributed in the southeastern United States, while A. ocreata is found on the West Coast and in the Southwest. Other similar toxic North American species include Amanita magnivelaris, which has a cream-colored, rather thick, felted-submembranous, skirt-like ring, and A. virosiformis, which has elongated spores that are 3.9–4.7 by 11.7–13.4 μm. Neither A. elliptosperma nor A. magnivelaris typically turn yellow with the application of KOH; the KOH reaction of A. virosiformis has not been reported.
Leucoagaricus leucothites is another all-white mushroom with an annulus, free gills, and white spore print, but it lacks a volva and has thick-walled dextrinoid (staining red-brown in Melzer's reagent) egg-shaped spores with a pore. A. bisporigera may also be confused with the larger edible species Agaricus silvicola, the "horse-mushroom". Like many white amanitas, young fruit bodies of A. bisporigera, still enveloped in the universal veil, can be confused with puffball species, but a longitudinal cut of the fruit body reveals internal structures in the Amanita that are absent in puffballs. In 2006, seven members of the Hmong community living in Minnesota were poisoned with A. bisporigera because they had confused it with edible paddy straw mushrooms (Volvariella volvacea) that grow in Southeast Asia.


The coastal giant salamander (Dicamptodon tenebrosus) is a species of salamander in the family Dicamptodontidae (Pacific giant salamanders).  It is endemic to the Pacific Northwest of North America. There are three closely related species to this taxon: D. ensatus (California giant salamander), D. copei (Cope's giant salamander), and D. aterrimus (Idaho giant salamander).


Aquatic stages are found in clear, cool or cold, well-oxygenated streams, and sometimes also in mountain lakes and ponds. Metamorphosed adults are found in humid forests (under rocks and logs, etc.), near mountain streams, or rocky shores of mountain lakes.


The coastal giant salamander can reach up to 34 cm (13 inches) in total length, making it the largest terrestrial salamander in North America. The coastal giant salamander has stout limbs with four toes on the front feet and five toes on the back feet. The species tail is around 40 percent of the total length of the salamander and is laterally compressed. The head, back, and sides have a marbled or reticulate pattern of dark blotches on a light brown or brassy-colored background. The head is broad with a shovel-like snout and a fold of skin across the throat called the gular fold. The eyes are medium in size and have a brass-flecked iris and a large black pupil. This species is one of the few salamanders capable of vocalizing.


A female coastal giant salamander will lay her eggs in moderate to slow flowing mountain streams under rocks and crevasses, hatching in early to mid spring. The coastal giant salamander, being a member of the genus Dicamptodon, exhibits two distinctive phases within its life; an aquatic larval stage with filamentous gills and an elongated tail with a caudal fin (similar to that of a tadpole), and a  terrestrial adult form losing their caudal fin and filamentous gills, and instead developing robust legs and a pair of internal lungs.


When threatened an adult coastal giant salamander will arch its back and lash its tail forward.  Coastal giant salamanders excrete toxins through their skin which will cause nausea if consumed.  Adult coastal giant salamanders can produce a painful bite.


The cap is 1–7 cm; broadly convex to plane, becoming nearly flat with age; often with a central depression. The surface is nearly bald, or fibrillose to scaly. Cap is hygrophanous, dark purple, purple, fading to brownish purple or buff.
The gills are attached to the stem, sub-distant to distant, purple fading to dull lilac or grayish purple. The stem is 1.5–12 cm long and 0.5–1.5 cm thick, equal or slightly swollen at the base and strongly grooved, with striated, coarse hairy or scaly purplish to pale purple color. The flesh is thin purple to whitish. The mushroom is edible.
Spores are 7.5–10.5 x 7–16 µm, subglobose or broadly elliptical. The spore print is white.


Laccaria amethysteo-occidentalis is a mushroom found under conifers, usually pine, growing alone, scattered or gregariously in western North America.


This species is similar to  L. amethystina but differs by occurring than hard wood forest and in Eastern North America, rather than conifers forest; having a smaller sporocarp; and being a lighter purple color. L. bicolor is smaller and less purplish; L. laccata has whitish mycelium at its base. Cortinarius violaceus is darker and has a less fibrillose stipe.


The Nile monitor is Africa's longest lizard. They grow from about 120 to 220 cm (3 ft 11 in to 7 ft 3 in) in length, with the largest specimens attaining 244 cm (8 ft). In an average-sized specimen, the snout-to-vent length will be around 50 cm (1 ft 8 in). In body mass, adults have been reported to vary widely, one study claiming only 0.8 to 1.7 kg (1.8 to 3.7 lb), others state weights ranging from 5.9 to 15 kg (13 to 33 lb) in big monitors. Variations may be due to age or environmental conditions. Exceptionally large specimens may scale as much as 20 kg (44 lb), but this species weighs somewhat less on average than the bulkier rock monitor. They have muscular bodies, strong legs, and powerful jaws. Their teeth are sharp and pointed in juvenile animals and become blunt and peg-like in adults. They also possess sharp claws used for climbing, digging, defense, or tearing at their prey. Like all monitors, they have forked tongues, with highly developed olfactory properties. The Nile monitor has quite striking, but variable, skin patterns, as they are greyish-brown above with greenish-yellow barring on the tail and large, greenish-yellow rosette-like spots on their backs with a blackish tiny spot in the middle. Their throats and undersides are an ochre-yellow to a creamy-yellow, often with faint barring.
Their nostrils are placed high on their snouts, indicating these animals are very well adapted for an aquatic lifestyle. They are also excellent climbers and quick runners on land. Nile monitors feed on a wide variety of prey items, including fish, frogs, toads (even poisonous ones of the genera Breviceps and Sclerophrys), small reptiles and birds, rodents, other small mammals (up to domestic cats and young antelopes [Raphicerus]), eggs, invertebrates, and carrion.


Nile monitors are native to Sub-Saharan Africa and along the Nile. They are not found in any of the desert regions of Africa (notably Sahara, Kalahari and much of the Horn of Africa), however, as they thrive around rivers. Nile monitors were reported to live in and around the Jordan River, Dead Sea, and wadis of the Judaean Desert in Israel until the late 19th century, though they are now extinct in the region.


The short-tail stingray is common and widely distributed in the temperate waters of the Southern Hemisphere. Off southern Africa, it has been reported from Cape Town in South Africa to the mouth of the Zambezi River in Mozambique. Along the southern Australian coast, it is found from Shark Bay in Western Australia to Maroochydore in Queensland, including Tasmania. In New Zealand waters, it occurs off North Island and the Chatham Islands, and rarely off South Island and the Kermadec Islands. Records from northern Australia and Thailand likely represent misidentifications of pink whipray and pitted stingray, respectively. Over the past few decades, its range and numbers off southeastern Tasmania have grown, possibly as a result of climate change.
Off southern Africa, the short-tail stingray is rare in shallow water and is most often found over offshore banks at a depth of 180 to 480 m (590 to 1,570 ft). However, off Australia and New Zealand, it was found from the intertidal zone to no deeper than 156 m (512 ft). Australian and New Zealand rays were most abundant in the shallows during the summer. A tracking study conducted on two New Zealand rays suggests that they shifted to deeper waters during the winter, but did not undertake long-distance migrations. The short-tail stingray is mainly bottom-dwelling in nature, inhabiting a variety of environments including brackish estuaries, sheltered bays and inlets, sandy flats, rocky reefs, and the outer continental shelf. However, it also makes regular forays upward into the middle of the water column.


The short-tail stingray is usually slow-moving, but can achieve sudden bursts of speed, flapping its pectoral fins with enough force to cavitate the water and create an audible "bang". Cavitation is when a liquid is pushed faster that it can react, causing a drop in pressure. It is known to form large seasonal aggregations; a well-known example occurs every summer (January to April) at the Poor Knights Islands off New Zealand, particularly under the rocky archways. In some areas, it moves with the rising tide into very shallow water. Individual rays tend to stay inside a relatively small home range with a radius of under 25 km (16 mi). Captive experiments have shown it capable of detecting magnetic fields via its electroreceptive ampullae of Lorenzini, which in nature may be employed for navigation.
The short-tail stingray forages for food both during the day and at night. It feeds primarily on benthic bony fishes and invertebrates, such as molluscs and crustaceans. The lateral line system on its underside allows it to detect the minute water jets produced by buried bivalves and spoon worms, which are then extracted by suction; the excess water is expelled through the spiracles. Fishes and invertebrates from open water, including salps and hyperiid amphipods, are also eaten in significant quantities. Off South Africa, this ray has been observed patrolling the egg beds of the chokka squid (Loligo vulgaris reynaudii) during mass spawnings, capturing squid that descend to the bottom to spawn. The short-tail stingray has few predators due to its size; these included the copper shark, the smooth hammerhead, the great white shark, and the killer whale. When threatened, it raises its tail warningly over its back like a scorpion. Smaller fishes have been observed using swimming rays for cover while hunting their own prey. Known parasites of this species include the nematode Echinocephalus overstreeti, and the monogeneans Heterocotyle tokoloshei and Dendromonocotyle sp.


The short-tail stingray or smooth stingray (Bathytoshia brevicaudata) is a common species of stingray in the family Dasyatidae. It occurs off southern Africa, typically offshore at a depth of 180–480 m (590–1,570 ft), and off southern Australia and New Zealand, from the intertidal zone to a depth of 156 m (512 ft). It is mostly bottom-dwelling in nature and can be found across a range of habitats from estuaries to reefs, but also frequently will swim into open water. One of the largest stingrays in the world, this heavy-bodied species can grow upwards of 2.1 m (6.9 ft) across and 350 kg (770 lb) in weight. Its plain-colored, diamond-shaped pectoral fin disc is characterized by a lack of dermal denticles even in adults, and white pores beside the head on either side. The body can have colors as well as dark grey or black with rows of white spots along each wing. Its tail is usually shorter than the disc and thick at the base. It is armed with large tubercles and a midline row of large thorns in front of the stinging spine which has the dorsal and ventral fin folds behind.
The diet of the short-tail stingray consists of invertebrates and bony fishes, including burrowing and midwater species. It tends to remain within a relatively limited area throughout the year, preferring deeper waters during the winter, and is not known to perform long migrations. Large aggregations of rays form seasonally at certain locations, such as in the summer at the Poor Knight Islands off New Zealand. Both birthing and mating have been documented within the aggregations at Poor Knights. This species is aplacental viviparous, with the developing embryos sustained by histotroph ("uterine milk") produced by the mother. The litter size is typically 6 –10, but litter sizes of up to fifteen are not unheard of.
The short-tail stingray is not aggressive, but is capable of inflicting a lethal wound with its long, venomous sting. It is often caught incidentally by commercial and recreational fisheries throughout its range, usually surviving to be released. Because its population does not appear threatened by human activity, the International Union for Conservation of Nature (IUCN) lists it under least concern.


The original description of the short-tail stingray was made by Frederick Hutton, curator of the Otago Museum, from a female specimen 1.2 m (3.9 ft) across caught off Dunedin in New Zealand. He published his account in an 1875 issue of the scientific journal Annals and Magazine of Natural History, in which he named the new species Trygon brevicaudata, derived from the Latin brevis ("short") and cauda ("tail"). Although long assigned to Dasyatis, recent work by Last et al. (2016) resurrected Bathytoshia for it and the broad stingray, as well as the roughtail stingray. The short-tail stingray may also be referred to as giant black ray, giant stingray, New Zealand short-tail stingaree, Schreiners ray, short-tailed stingaree, shorttail black stingray, and smooth short-tailed stingray. It is closely related to the similar-looking but smaller pitted stingray (Dasyatis matsubarai) of the northwestern Pacific.


White-footed mice are omnivorous, and eat seeds and insects. They are timid and generally avoid humans, but they occasionally take up residence in ground-floor walls of homes and apartments, where they build nests and store food.


The white-footed mouse (Peromyscus leucopus) is a rodent native to North America from Ontario, Quebec, Labrador, and the Maritime Provinces (excluding the island of Newfoundland) to the southwestern United States and Mexico. In the Maritimes, its only location is a disjunct population in southern Nova Scotia. It is also known as the woodmouse, particularly in Texas.


Adults are 90–100 mm (3.5–3.9 in) in length, not counting the tail, which can add another 63–97 mm (2.5–3.8 in). A young adult weighs 20–30 g (0.7–1.1 oz). While their maximum lifespan is 96 months, the mean life expectancy for the species is 45.5 months for females and 47.5 for males. In northern climates, the average life expectancy is 12–24 months. The species is similar to Peromyscus maniculatus.


Hygrocybe flavescens is a species of Hygrocybe described from Michigan. It is considered nonpoisonous to humans. The species can be found in various forests and woodlands.
The mushroom is yellow-orange. Its cap ranges from 2.5 to 6 cm wide, and can be more orange in youth. The stalk is 4 to 7 cm long, .5 to 1.5 cm wide. The gills are more pale than the cap and stipe. The spores are white, elliptical, smooth and inamyloid. It has a mild taste and odor.
Hygrocybe chlorophana is similar, noted in North America as having a more viscid stipe. This distinction is not made in Europe, indicating that they may be the same species.


The porcupinefish is found in all the tropical and subtropical waters of the world, including the Mediterranean Sea.
Juveniles are pelagic up to the time that they are about 20 cm in length. Adults favour lagoons, top reefs and seaward coral or rocky reefs from one to 50 m depth, sheltering under ledges or in caves during the day.


As with most fish, the porcupinefish is infected by a variety of parasites. Spectacular parasites are the cysts of the larvae of the trypanorhynch cestode Molicola horridus, often found in great numbers in the liver. These parasites represent no danger to humans.


The porcupinefish's diet is based on Sea urchins, gastropods and crustaceans.


The spot-fin porcupinefish is a medium-sized fish which grows up to 91 cm, but the average size mostly observed is 40 cm.
Its body is elongated with a spherical head with big round protruding eyes, and a large mouth which is rarely closed.
The pectoral fins are large, the pelvic fins are absent, and the anal and dorsal fins are close to the caudal peduncle. The latter move simultaneously during swimming.
The skin is smooth and firm; the scales are modified into spines.
The body coloration is beige to sandy-yellow marbled with dark blotches and dotted with numerous small black spots.
In case of danger, the porcupinefish can inflate itself by swallowing water to deter the potential predator with its larger volume and it can raise its spines.
The porcupinefish concentrates tetrodotoxin in certain parts of its body such as the liver, skin, gonads and the viscera. This defensive system constitutes an additional device to dissuade potential predators.


In southern Florida, N. floridana is active year round.  Like other water snakes of the southeastern U.S., N. floridana hibernates during the winter in the northern, coldest parts of its range. In colder areas and months, the snake can be seen basking outdoors on sunny days. In southern Florida, it often travels overland  on rainy days.
Little is known about the diet of the N. floridana. Most reports suggest that their diet consists primarily of fish, including sunfish, crappies, and small bass. They also feed on frogs, especially pig frogs, tadpoles and salamander. Little is known about their methods for finding prey, but like other water snakes, the N. floridana swallows its prey alive.


N. floridana 's distribution is generally throughout Florida and in parts of southern Georgia. It is commonly found in southern South Carolina in open, marshy wetland areas. The snake is rarely found in  rivers or streams. N. floridana prefers choked vegetation and calm waters such as swamps and marshes. It is also generally found in lakes, ponds, ditches, and occasionally in brackish water.


This species bears live young (ovoviviparous) like other North American water snakes. A few observations have been made of matings in late winter or early spring. Females generally have very large litters and give birth in the summer. The size of the litter ranges from 20 to 40, and the young are typically born from June to September. The record litter for the species was 132 babies, taken from a dead female.


The common brushtail possum is perhaps the most widespread marsupial of Australia. It is found throughout the eastern and northern parts of the continent, as well as some western regions, Tasmania and a number of offshore islands, such as Kangaroo Island and Barrow Island. It is also widespread in New Zealand since its introduction in 1850. The common brushtail possum can be found in a variety of habitats, such as forests, semi-arid areas and even cultivated or urban areas. It is mostly a forest inhabiting species, however it is also found in treeless areas. In New Zealand, possums favour broadleaf-podocarp near farmland pastures. In  southern beech forests and pine plantations, possums are less common. Overall, brushtail possums are more densely populated in New Zealand than in their native Australia. This may be because Australia has more fragmented eucalypt forests and more predators. In Australia, brushtail possums are threatened by humans, tiger quolls, dogs, foxes, cats, goannas, carpet snakes, and powerful owls. In New Zealand, brushtail possums are threatened only by humans and cats. The IUCN highlight the population trend in Australia as decreasing.


The common brushtail possum can adapt to numerous kinds of vegetation. It prefers Eucalyptus leaves, but also eats flowers, shoots, fruits, and seeds. It may also consume animal matter such as insects, birds' eggs and chicks, and other small vertebrates. Brushtail possums may eat three or four different plant species during a foraging trip, unlike some other arboreal marsupials, such as the koala and the greater glider, which focus on single species. The brushtail possum's rounded molars cannot cut Eucalyptus leaves as finely as more specialised feeders. They are more adapted to crushing their food, which enables them to chew fruit or herbs more effectively. The brushtail possums' caecum lacks internal ridges and cannot separate coarse and fine particles as efficiently as some other arboreal marsupials. The brushtail possum cannot rely on Eucalyptus alone to provide sufficient protein. Its more generalised and mixed diet, however, does provide adequate nitrogen.


The common brushtail possum (Trichosurus vulpecula, from the Greek for "furry tailed" and the Latin for "little fox", previously in the genus Phalangista) is a nocturnal, semiarboreal marsupial of the family Phalangeridae, native to Australia and naturalised in New Zealand, and the second-largest of the possums.
Like most possums, the common brushtail possum is nocturnal. It is mainly a folivore, but has been known to eat small mammals such as rats. In most Australian habitats, eucalyptus leaves are a significant part of the diet, but rarely the sole item eaten. Its tail is prehensile and naked on its lower underside. The four colour variations are silver-grey, brown, black, and gold.
It is the Australian marsupial most often seen by city dwellers, as it is one of few that thrive in cities and a wide range of natural and human-modified environments. Around human habitations, common brushtails are inventive and determined foragers with a liking for fruit trees, vegetable gardens, and kitchen raids.
The common brushtail possum was introduced to New Zealand in the 1850s to establish a fur industry, but in the mild subtropical climate of New Zealand, and with few to no natural predators, it thrived to the extent that it became a major agricultural and conservation pest.


The common brushtail possum can breed at any time of the year, but breeding tends to peak in spring, from September to November, and in autumn, from March to May, in some areas. Mating is promiscuous and random; some males can sire several young in a season, while over half sire none. In one Queensland population, males apparently need a month of consorting with females before they can mate with them. Females have a gestation period of 16–18 days, after which they give birth to single young. A newborn brushtail possum is only 1.5 cm long and weighs only 2 g. As usual for marsupials, the newborn may climb, unaided, through the female's fur and into the pouch and attach to a teat. The young develops and remains inside the mother's pouch for another 4–5 months. When older, the young is left in the den or rides on its mother's back until it is 7–9 months old. Females reach sexual maturity when they are a year old, and males do so at the end of their second year. Brushtail possums can live up to 13 years in the wild.
Female young have a higher survival rate than their male counterparts due to establishing their home ranges closer to their mothers, while males travel farther in search of new nesting sites, encountering established territories from which they may be forcibly ejected. In New Zealand's Ōrongorongo population, female young have been found to continue to associate with their mothers after weaning, and some inherit the prime den sites. A possible competition exists between mothers and daughters for dens, and daughters may be excluded from a den occupied by the mother. In forests with shortages of den sites, females apparently produce more sons, which do not compete directly for den sites, while in forests with plentiful den sites, female young are greater in number.


B. plumifrons are an omnivorous species, their diet is inclusive of both meat and vegetation. While meat may be a stretch from their typical consumption, they choose to eat a large variety of insects and worms. While they are capable of consuming vegetation (such as fruits, seeds, flowers, and leaves), it is less sought out in the wild as opposed to captivity for the B. plumifrons. While they do hunt smaller sized animals such as fish, small mammals (such as rodents), small birds, small nonvenomous snakes, smaller species of lizards, amphibians, and invertebrates (crustaceans [such as freshwater shrimp and crayfish] and spiders), they are most often found in search of insects for their diet.
They typically consume brown crickets, black crickets, and locusts. In captivity, some owners choose to feed their B. plumifrons or green crested lizard wax worms, calciworms, cockroaches, mealworms, and beetle worms on occasion. This latter selection of worms, roaches, and beetles are not the best suitable for the B. plumifrons diet as they are found to be high in fat and can be difficult to digest for juvenile B. plumifrons.


The plumed basilisk (Basiliscus plumifrons), also called the green basilisk,  double crested basilisk, or  Jesus Christ lizard, is a species of lizard in the family Corytophanidae. The species is native to Central America.
The plumed basilisk's native range spans southern Mexico and northern Colombia. B. plumifrons inhabits hot, humid rainforests that contain streams, rivers or other water bodies.
The physical appearance of the plumed basilisk is striking: it sports a bright green color along its body with black and white streaks along its neck and back. Their physical appearance differs by sex, as they are sexually dimorphic; males have a distinct crest on the back and tail and large plumes on top of their heads, while females typically only have a singular, much smaller, crest on their head.
The green crested or plumed lizard is unique in its ability to run across water with speed and the method it employs to do this. It displays the behaviour as a threat response, when fleeing predators. High speed is maintained in order to prevent sinking.
This lizard is extraordinarily territorial and is known for its aggressive behaviour to the extent that multiple male lizards cannot be maintained within the same enclosure. However, they do exist in the wild in large groups that allow for multiple males.


The plumed basilisk is the largest basilisk species, with an average snout-to-vent length (SVL) of 10 inches (25 cm). Including the tail, it can reach 3 feet (91 cm) in total length. Adults are brilliant green, with bright yellow eyes, and small bluish spots along the dorsal ridge. Males have three crests: one on the head, one on the back, and one on the tail, while females have only the head crest. Juveniles are less conspicuously colored, and lack the characteristic crests.
The green crested basilisk of B. plumifrons is a bright green lizard species found with varying streaks of white dark grey, and blue markings along its body. However, some alternative forms or subspecies of B. plumifrons have been seen to sport only black markings along its dorsal side. The underbelly of this lizard is typically a lighter shade of green than the bright green that is shown throughout its body. Its head is triangular from side view or profile, with openings for ears. These openings are slightly larger than the size of their eyes. The B. plumifrons mostly have round eyes, round pupils, and yellow irises. Small granular scales comprise the main covering for their skin. The length of the hind legs are longer than the front limbs as the hind legs are used for water running. In addition, their toes are laterally angled and flat to allow for water running. Adult males have four prominent vertebral crests: a dorsal crest, a tail crest, one atop the crown of the head, and one between their eyes. These crests form the greater physical distinction between female and male plumed basilisks. The females have only two reduced crests: a tail crest, and head crest. This characteristic is shared with the juveniles if the species.


B. plumifrons’ habitat is restricted to rainforests that are in close proximity to running streams, such as occur in southern Mexico and northern Colombia. Moist lowlands of wet, mature forest, with running streams are their preferred environments. Their habitat is typically hot and humid.
Agroforestry systems, with the integration of forest life (trees), is necessary for the preservation of the B. plumifrons species. While the plumed basilisk is native to southern Mexico and northern Colombian rainforests, there is evidence to suggest that it occupies land across the Atlantic versant spanning eastern Honduras to western Panama. Additionally, B. plumifrons have been sighted along the Pacific coast in southwestern Costa Rica.
B. plumifrons is arboreal (preferential to tree landscape for their habitat), and diurnally active (active during the day). Of the three species of Basiliscus present in Costa Rica each is found commonly on both versants (borders of land). B. plumifrons are aquatic lizards, found in high prevalence and widespread in Central American inland rivers, streams, ponds, and lakes, in addition to beaches and seashores. This species is unique in that it is both arboreal and aquatic and can be found in large numbers in both trees and perched on boulders near bodies of water.
The temperature preference of the B. plumifrons is between 31.7°C +/- 0.5.


During the week prior to laying, sexually mature females of B. plumifrons were observed presenting herself to the male. The female would position herself about 0.5 m from the male, lowering her forebody to the sand and raising her pelvic region and tail.  Females lay five to fifteen eggs at a time in warm, damp sand or soil.  One mother lizard in captivity actually was observed to start digging holes (sometimes referred to as nests) in the soil six months prior to ovipositing, well ahead of the breeding season. The eggs hatch after eight to ten weeks, at which point they emerge as fully independent lizards, although averaging only 43mm SVL (Snout-to-Vent Length) and weighing only about 2 grams. The juvenile males would start to develop the large crests which are characteristic of the male B. plumifrons after six month or up to more than one year, depending on the body conditions of the juveniles.
Female B. plumifrons are start showing or become plump one to two weeks post-fertilization. During the third week of gestation, females will begin to search for a site to burrow or lay approximately 14-17 eggs. Typically, the size (no. in quantity of eggs) will vary depending on the lifestyle and physical characteristics of the mother (i.e. age, health, and size). It is common for plumed basilisk females to lay multiple clutches within a given season and this event will occur up to four or five times during a given breeding season. Hatching of eggs occurs over a one to two day period after a gestation and incubation period of eight to ten weeks.


In captivity, the Greek tortoise loves dandelion leaves and other leafy plants. However, although they also enjoy eating lettuce, it is not recommended to them due to having a lack of nutrients that the tortoises need to survive.


The Greek tortoise is commonly traded as a pet in source countries such as Morocco and Spain, despite the illegality of this trade. This can lead to an unsustainable removal of wild individuals for the local pet trade and for export. Also, welfare concerns exist with this trade, as the animals are not properly housed when being sold, causing a high rate of mortality in captivity.


The division of the Greek tortoise into subspecies is difficult and confusing. Given their huge range over three continents, the various terrains, climates, and biotopes have produced a huge number of varieties, with new subspecies constantly being discovered. Currently, at least 20 subspecies are published:
T. g. graeca (North Africa and South Spain)
T. g. soussensis (South Morocco)
T. g. marokkensis (North Morocco)
T. g. nabeulensis - Tunisian tortoise (Tunisia)
T. g. cyrenaica (Libya)
T. g. ibera (Turkey)
T. g. armeniaca - Armenian tortoise (Armenia)
T. g. buxtoni (Caspian Sea)
T. g. terrestris (Israel/Lebanon)
T. g. zarudnyi (Iran/Azerbaijan)
T. g. whitei (Algeria)
T. g. floweri (Jordan)
This incomplete listing shows the problems in the division of the species into subspecies. The differences in form are primarily in size and weight, as well as coloration, which ranges from dark brown to bright yellow, and the types of flecks, ranging from solid colors to many spots. Also, the bending-up of the edges of their carapaces ranges from minimal to pronounced. So as not to become lost in the number of subspecies, recently, a few tortoises previously classified as T. graeca have been assigned to different species, or even different genera.
The genetic richness of T. graeca is also shown in its crossbreeding. Tortoises of different form groups often mate, producing offspring with widely differing shapes and color. Perhaps the best means of identification for the future is simply the place of origin.
The smallest, and perhaps the prettiest, of the subspecies, is the Tunisian tortoise. It has a particularly bright and striking coloration. However, these are also the most sensitive tortoises of the species, so they cannot be kept outdoors in temperate climates, as cold and rainy summers quickly cause the animals to become ill. They are also incapable of long hibernation.
At the other extreme, animals from northeastern Turkey are very robust, such as Hermann's tortoise. The largest specimens come from Bulgaria. Specimens of 7 kg (15 lb) have been reported. In comparison, the Tunisian tortoise has a maximum weight of 0.7 kg (1.5 lb). T. graeca is also closely related to the marginated tortoise (T. marginata). The two species can interbreed, producing offspring capable of reproduction.


In T. graeca, immediately after waking from hibernation, the mating instinct starts up. The males follow the females with great interest, encircling them, biting them in the limbs, ramming them, and trying to mount them. During copulation, the male opens his mouth, showing his red tongue and making squeaking sounds.
During mating, the female stands still, bracing herself with her front legs, moving the front part of her body to the left and right in the same rhythm as the male's cries. One successful mating will allow the female to lay eggs multiple times. When breeding in captivity, the pairs of females and males must be kept separate. If multiple males are in a pen, one takes on a dominant role and will try to mate with the other males in the pen. If more males than females are in a pen, the males might kill each other to mate with the females.
One or two weeks before egg laying, the animals become notably agitated, moving around to smell and dig in the soil, even tasting it, before choosing the ideal spot to lay the eggs. One or two days before egg laying, the female takes on an aggressive, dominant behavior, mounting another animal as for copulation and making the same squeaking sound the male produces during copulation. The purpose of this behavior is to produce respect in the tortoise community so that the female will not be disturbed by the others during egg laying. Further details of egg-laying behavior are the same as those detailed for the marginated tortoise.


The Greek tortoise (Testudo graeca), also known commonly as the spur-thighed tortoise, is a species of tortoise in the family Testudinidae. Testudo graeca is one of five species of Mediterranean tortoises (genera Testudo and Agrionemys). The other four species are Hermann's tortoise (T. hermanni), the Egyptian tortoise (T. kleinmanni), the marginated tortoise (T. marginata), and the Russian tortoise (A. horsfieldii). The Greek tortoise is a very long-lived animal, achieving a lifespan upwards of 125 years, with some unverified reports up to 200 years.


The Aesculapian snake /ˌɛskjəˈleɪpiən/ (now Zamenis longissimus, previously Elaphe longissima), is a species of nonvenomous snake native to Europe, a member of the Colubrinae subfamily of the family Colubridae. Growing up to 2 metres (6.6 ft) in length, it is among the largest European snakes, similar in size to the four-lined snake (Elaphe quatuorlineata) and the Montpellier snake (Malpolon monspessulanus). The Aesculapian snake has been of cultural and historical significance for its role in ancient Greek, Roman and Illyrian mythology and derived symbolism.


Their main food source are rodents up to the size of rats (a 130 cm adult specimen has been reported to have overpowered a 200g rat) and other small mammals such as shrews and moles. They also eat birds as well as bird eggs and nestlings. They suffocate their prey by constriction, though harmless smaller mouthfuls may be eaten alive without constriction, or simply crushed on eating by jaws. Juveniles mainly eat lizards and arthropods, later small rodents. Other snakes and lizards are taken, but only found rarely in adult prey.
Predators include badgers and other mustelids, foxes, wild boar (mainly by digging up and decimating hatches and newborns), hedgehogs, and various birds of prey (though there are reports of adults successfully standing their ground against feathered attackers). Juveniles may be eaten by smooth snakes and other reptilivorous snakes. Also a threat mainly to juveniles and hatches are domestic animals such as cats, dogs, and chickens, and even rats may be dangerous to inactive adult specimens in hibernation. In areas of concurrent distribution, they are also preyed upon by introduced North American raccoons and east Asian raccoon dogs.


The Aesculapian snake prefers forested, warm but not hot, moderately humid but not wet, hilly or rocky habitats with proper insolation and varied, not sparse vegetation that provides sufficient variation in local microclimates, helping the reptile with thermoregulation. In most of their range they are typically found in relatively intact or fairly cultivated warmer temperate broadleaf forests including the more humid variety such as along river valleys and riverbeds (but not marshes) and forest steppes. Frequented locations include places such as forest clearings in succession, shrublands at the edges of forests and forest/field ecotones, woods interspersed with meadows etc. However, they generally do not avoid human presence, being often found in places such as gardens and sheds, and even prefer habitats such as old walls and stonewalls, derelict buildings and ruins that offer a variety of hiding and basking places. The synanthropic aspect appears to be more pronounced in northernmost parts of the range where they are dependent on human structures for food, warmth and hatching grounds. They avoid open plains and agricultural deserts.
In the south their range seems to coincide with the borderline between deciduous broadleaf forests and Mediterranean shrublands, with the latter presumably too dry for the species. In the north their line of presence appears temperature-limited.


Minimum length of individuals entering the reproductive cycle has been reported at 85–100 cm, which corresponds to sexual maturity age of about 4–6 years. Breeding occurs annually after hibernation in spring, typically from mid-May to mid-June. In this time the snakes actively seek each other and mating begins. Rival males engage in ritual fights the aim of which is to pin down the opponent's head with one's own or coils of one's body; biting may occur but is not typical. The actual courtship takes the form of an elegant dance between the male and female, with anterior portions of the bodies raised in an S-shape and the tails entwined. The male may also grasp the female's head with its jaw (Lotze 1975). 4 to 6 weeks after about 10 eggs are laid (extremes are from 2 to 20, with 5–11 on average) in a moist, warm spot where organic decomposition occurs, usually under hay piles, in rotting wood piles, heaps of manure or leaf mold, old tree stumps and similar places. Particularly in the northern parts of the range, preferred hatching grounds often are used by multiple females and are also shared with grass snakes. The eggs incubate for around 8 (6 to 10) weeks before hatching.


Z. longissimus hatches at around 30 cm (11.8 in). Adults are usually from 110 cm (43.3 in) to 160 cm (63 in) in total length (including tail), but can grow to 200 cm (79 in), with the record size being 225 cm (7.38 ft). Expected body mass in adult Aesculapian snakes is from 350 to 890 g (0.77 to 1.96 lb). It is dark, long, slender, and typically bronzy in colour, with smooth scales that give it a metallic sheen.
Juveniles can easily be confused with juvenile grass snakes (Natrix natrix) and barred grass snakes (Natrix helvetica), because juvenile Aesculapians also have a yellow collar on the neck that may persist for some time in younger adults. Juvenile Z. longissimus are light green or brownish-green with various darker patterns along the flanks and on the back. Two darker patches appear in the form of lines running on the top of the flanks. The head in juveniles also features several distinctive dark spots, one hoof-like on the back of the head in-between the yellow neck stripes, and two paired ones, with one horizontal stripe running from the eye and connecting to the neck marks, and one short vertical stripe connecting the eye with the fourth to fifth upper labial scales.
Adults are much more uniform, sometimes being olive-yellow, brownish-green, sometimes almost black. Often in adults, there may be a more or less regular pattern of white-edged dorsal scales appearing as white freckles all over the body up to moiré-like structures in places, enhancing the shiny metallic appearance. Sometimes, especially when pale in colour, two darker longitudinal lines along the flanks can be visible. The belly is plain yellow to off-white, while the round iris has amber to ochre colouration. Melanistic, erythristic, and albinotic natural forms are known, as is a dark grey form.
Although there is no noticeable sexual dimorphism in colouration, males grow significantly longer than females, presumably because of the more significant energy input of the latter into the reproductive cycle. Maximum weight for German populations has been 890 grams (1.96 lb) for males and 550 grams (1.21 lb) for females (Böhme 1993; Gomille 2002). Other distinctions, as in many snakes, include in males a relatively longer tail to total body length and a wider tail base.
Scale arrangement includes 23 dorsal scale rows at midbody (rarely 19 or 21), 211-250 ventral scales, a divided anal scale, and 60-91 paired subcaudal scales (Schultz 1996; Arnold 2002). Ventral scales are sharply angled where the underside meets the side of the body, which enhances the species' climbing ability.
Lifespan is estimated at 25 to 30 years.


Yellow bullhead are bottom dwellers, living in areas with muck, rock, sand, or clay substrates. Its habitat includes river pools, backwaters, and sluggish current over soft or mildly rocky substrate in creeks, small to larger rivers, and shallow portions of lakes and ponds. Their habitat can vary from a slow current with poorly oxygenated, highly silted, and highly polluted water to a more swift current with clean and clear water that has aquatic vegetation. Fishermen often find them in sluggish creeks and rivers with a gravel bottom.


Yellow bullhead have a wide range across the central and eastern US from the Rio Grande River to North Dakota and south-eastern Canada, and east through the Great Lakes region to the East Coast.  They have also been introduced to the West and can be caught as far up as northern Washington state.


The yellow bullhead is a voracious scavenger that will almost eat anything. It locates prey by brushing the stream bottom with its barbels. Taste buds on the barbels tell the yellow bullhead whether or not contact is made with edible prey. They typically feed at night on a variety of plant and animal material, both live and dead, most commonly consisting of worms, insects, snails, minnows, clams, crayfish, other small aquatic organisms, plant matter, and decaying animal matter. Compared to black and brown bullheads, yellow bullheads consume more aquatic vegetation.


The yellow bullhead is a medium-sized member of the catfish family. It is typically yellow-olive to slate black on the back and may appear mottled depending on its habitat. The sides are lighter and more yellowish, while the underside of the head and body are bright yellow, yellow white, or bright white. The rear edge of its caudal fin is rounded. The anal fin is much longer than those of other bullheads, having anywhere between 24 and 27 rays. The yellow bullhead, though less common, can be easily distinguished from the brown bullhead and black bullhead by the group of white barbels or "whiskers" under its chin. Yellow bullheads are medium-sized bullheads that rarely grow larger than 2 lb (0.91 kg), but can reach up to 6.375 lb (2.892 kg). Yellow bullheads range in size from 6 to 14 inches, and can live up to 12 years.


The leopard shark (Triakis semifasciata) is a species of houndshark, in the family Triakidae. It is found along the Pacific coast of North America, from the U.S. state of Oregon to Mazatlán in Mexico. Typically measuring 1.2–1.5 m (3.9–4.9 ft) long, this slender-bodied shark is immediately identifiable by the striking pattern of black saddle-like markings and large spots over its back, from which it derives its common name. Large schools of leopard sharks are a common sight in bays and estuaries, swimming over sandy or muddy flats or rock-strewn areas near kelp beds and reefs. They are most common near the coast, in water less than 4 m (13 ft) deep.
Active-swimming predators, groups of leopard sharks often follow the tide onto intertidal mudflats to forage for food, mainly clams, spoon worms, crabs, shrimp, bony fish, and fish eggs. Most leopard sharks tend to remain within a particular area rather than undertaking long movements elsewhere, which has led to genetic divergence between populations of sharks living in different regions. This species is aplacental viviparous, meaning that the young hatch inside the uterus and are nourished by yolk. From March to June, the female gives birth to as many as 37 young after a gestation period of 10–12 months. It is relatively slow-growing and takes many years to mature.
Harmless to humans, the leopard shark is caught by commercial and recreational fisheries for food and the aquarium trade. This species is mostly fished in the waters off California where, after a period of population decline in the 1980s, new fishing regulations in the early 1990s reduced harvesting to sustainable levels. The International Union for Conservation of Nature has assessed this species as of Least Concern, while noting that local stocks may easily become overfished because of the shark's slow growth and limited migratory habits.


The diet of the leopard shark consists of small benthic and littoral animals, most significantly crabs (Cancridae, Grapsidae, and Hippoidea), shrimp, bony fish (including anchovies, herring, topsmelt, croakers, surfperch, gobies, rockfish, sculpins, flatfish, and midshipmen), fish eggs, clams, and the echiurid fat innkeeper worm (Urechis caupo). This opportunistic hunter has also been known to eat ghost shrimp, polychaete worms, and the young of smoothhounds, shovelnose guitarfish (Rhinobatos productus), and bat rays (Myliobatis californicus). Eelgrass (Zostera) and algae may be swallowed incidentally.
The leopard shark captures prey by expanding its buccal cavity to create a suction force, which is facilitated by its labial cartilages swinging forward to form the mouth into a tube. Simultaneously, the shark protrudes its jaws forward to grip the prey between its teeth. As with other sharks, the teeth of the leopard shark are periodically shed and replaced; it takes 9–12 days for a replacement tooth to move into position. Leopard sharks have been caught with stomachs filled with clam siphons, which the sharks seize before the clams can retract and break off with a levering motion of their bodies. On occasion, the shark tears the entire clam body out of its shell this way. Other sharks examined have had stomachs containing whole innkeeper worms with no bite marks, suggesting that the sharks sucked them out of their burrows. Under a hollow bridge support in San Francisco Bay, a group of leopard sharks and spiny dogfish have been observed feeding on a dense school of anchovies by slowly swimming counterclockwise through the clockwise-swimming school, and swallowing any anchovies that accidentally entered their open mouths.
In some places, this species feeds only on a few prey types and little else (e.g. innkeeper worms and cancrid crabs in Tomales Bay, jack silverside (Atherinopsis californiensis) eggs and the crabs Romaleon antennarium and Metacarcinus magister in Humboldt Bay). The predominant prey taken depends on location, time of year, and age. For example, in the Elkhorn Slough at Monterey Bay, cancrid crabs and innkeeper worms are mostly eaten in winter and spring, fish eggs from winter to early summer, bony fish in summer, and grapsid crabs and clams in fall. Young sharks feed mostly on crabs and transition to clam siphons, fish eggs, and innkeeper worms once they reach 70–80 cm (2.3–2.6 ft) long. The largest sharks are the ones that consume the most fish.


The leopard shark has a moderately stout body, with a short, rounded snout. There are well-developed, triangular flaps of skin in front of the nares. The eyes are large and oval, with a nictitating membrane (a protective third eyelid). The line of the mouth is strongly curved. There are furrows at the corners of the mouth extending onto both jaws, with those on the lower jaw almost long enough to meet at the midline. The tooth rows number 41–55 in the upper jaw and 34–45 in the lower jaw; each tooth has a slightly oblique, smooth-edged cusp in the center and 1–2 small cusplets on either side. These teeth are arranged into a flat, "pavement"-like surface with overlapping ridges.
The large first dorsal fin is positioned about halfway between the pectoral and pelvic fins; the second is almost as large as the first and much larger than the anal fin. The pectoral fins are wide and triangular. The lower lobe of the caudal fin is well-developed in adults but less than half the length of the upper lobe, which has a strong ventral notch near the tip. The coloration is unique, consisting of prominent black "saddles" and large black spots running along the back, on a silvery to bronzy gray background. Adult sharks often have more spots and saddles with lighter centers compared to juveniles. The underside is whitish and plain. The average length of a leopard shark is 1.2–1.5 m (3.9–4.9 ft). Rarely males may grow to 1.5 m (4.9 ft) and females 1.8 m (5.9 ft), and there is a record of an exceptional female that measured 2.1 m (6.9 ft) long. The heaviest known leopard shark weighed 18.4 kg (41 lb).


The first scientific name applied to the leopard shark was Triakis californica, coined by British zoologist John Edward Gray in the 1851 List of the specimens of fish in the collection of the British Museum. However, Gray did not furnish the name with a proper description, rendering it a nomen nudum. In December 1854, American ichthyologist William Orville Ayres gave a lecture describing the species as Mustelus felis, which included the first scientific description of the species.  His lecture was reprinted first in The Pacific, a San Francisco newspaper, and then in the journal Proceedings of the California Academy of Natural Sciences. In April 1855, French biologist Charles Frédéric Girard published another description of this species, naming it Triakis semifasciata.
Despite M. felis being the senior synonym, an error in recording the dates of publication resulted in the widespread use of T. semifasciata as the leopard shark's scientific name. As a result of this long-standing error, Triakis semifasciata came to be recognized as the valid name (as a nomen protectum) and Mustelis felis was invalidated (as a nomen oblitum). The specific epithet semifasciata comes from the Latin words semi ("half") and fasciatus ("banded"), describing this shark's dorsal pattern of saddle-like markings. In older literature, this species may be referred to as "tiger shark" or "catshark".
The genus Triakis contains two subgenera, Triakis and Cazon. The leopard shark is placed within the subgenus Triakis along with the banded houndshark (T. (Triakis) scyllium). A 2006 phylogenetic analysis by J. Andrés López and colleagues, based on protein-coding genes, revealed that Triakis and Cazon are in fact not closely related, and additionally that the leopard shark may be the most basal member of its family.


Previously, P. leucomystex was thought to distribute below the Red River of Vietnam and in western Yunnan, while P. megacephalus can be found above the Red River and in Northeast India. However, recent genetic studies revealed that the natural barriers between these species are the Isthmus of Kra and the Tenasserim Range, where P. leucomystax can be found below the isthmus and west of the range.
The Polypedates leucomystax complex began diverging during the Pliocene, and spread quickly after the Pleistocene due to human activity. The range of P. leucomystax has recently expanded in the Philippines and Indonesia due to the widespread conversion of forests into agricultural-use land. It is also frequently found in trans-island agricultural shipments. Lineages on the Indochina mainland are more diverse.
In Indonesia, it has been found throughout the archipelago in Borneo, Mentawai, Sumatra, Java, Sulawesi, Bali, Lombok, Natuna Islands, Anambas Islands, Sumbawa, Sumba, Flores, and Timor, and has also been introduced to Papua. In Japan, where it has been introduced, it is found on the islands of Okinawa, Tonaki, Kurima, Miyako, Ie, Iheya, Izena, Sesoko, and Yabuchi.
4 major haplotype clades of P. leucomystax have been recognized by Brown, et al. (2010), with the clades other than the southern Sunda region clade likely to be cryptic species.
southern Sunda region: Java–Sumatra ("true" P. leucomystax; type locality: Java)
northern Sunda region: Peninsular Malaysia, northern Borneo (Sarawak and Sabah), and southern Philippines (most basal clade)
Sulawesi (with the name P. celebensis sp. nov. suggested; 4 different sub-clades have been differentiated for each of the 4 "prongs" or peninsulas of Sulawesi Island)
northern Philippines (with the name P. quadrilineatus sp. nov. suggested; includes a basal variety from Lombok)
Divergent varieties that are either P. cf. leucomystax or P. cf. megacephalus have been found in southern China (including Hainan) and Vietnam.


Its natural habitats are subtropical or tropical dry forests, subtropical or tropical moist lowland forests, subtropical or tropical moist montane forests, subtropical or tropical moist shrubland, subtropical or tropical seasonally wet or flooded lowland grassland, rivers, intermittent rivers, freshwater lakes, intermittent freshwater lakes, freshwater marshes, intermittent freshwater marshes, freshwater springs, rocky shores, coastal freshwater lagoons, arable land, pastureland, plantations, rural gardens, urban areas, water storage areas, ponds, aquaculture ponds, irrigated land, seasonally flooded agricultural land, and introduced vegetation.


Polypedates leucomystax can reach approximately a snout–vent length of 3.7–5.0 centimetres (1.5–2.0 in) in males, of 5.7–7.5 millimetres (0.22–0.30 in) in females. Body of these rather small shrub frogs is moderately slender, ovoid, slightly flattened above, with sharply pointed tail. The skin on the upper side is smooth. The body colour is rather variable, with various shades of gray, green, yellow, reddish or dark brown. Usually it is irregularly mottled, often with four stripes along the back. The tip of snout sometimes shows a distinct white spot. Eyes are at the side of the head. The hind feet are webbed. The feet have clear, large cushions as usual with leaf frogs.


In the damp areas of the propagation, these frogs are present all year round. In drier environments, the period usually restricts to the beginning of the rainy season. The mating takes place at the margins of shallow pools, where the males first arrive and call the females with a distinctive loud, duck-like sound. The female places between 100 and 400 eggs in a protective foam nest that is attached to vegetation or other objects above the water surface. Mean egg diameter is 1.99mm (range of 1.9-2.1mm). The eggs hatch after 3 to 4 days. The tadpoles develop inside the foam nest and then fall into the water. They develop into adult frogs in about 7 weeks.


Tremella fuciformis has been cultivated in China since at least the nineteenth century. Initially, suitable wooden poles were prepared and then treated in various ways in the hope that they would be colonized by the fungus. This haphazard method of cultivation was improved when poles were inoculated with spores or mycelium. Modern production only began, however, with the realization that both the Tremella and its host species needed to be inoculated into the substrate to ensure success. The "dual culture" method, now used commercially, employs a sawdust mix inoculated with both fungal species and kept under optimal conditions. The most popular species to pair with T. fuciformis is its preferred host, Annulohypoxylon archeri. Estimated production in China in 1997 was 130,000 tonnes. Tremella fuciformis is also cultivated in other East Asian countries, with some limited cultivation elsewhere.
In Chinese cuisine, Tremella fuciformis is traditionally used in sweet dishes. While tasteless, it is valued for its gelatinous texture as well as its supposed medicinal benefits. Most commonly, it is used to make a dessert soup called luk mei (六味) in Cantonese, often in combination with jujubes, dried longans, and other ingredients. It is also used as a component of a drink and as an ice cream. Since cultivation has made it less expensive, it is now additionally used in some savoury dishes.
In Vietnamese cuisine, it's often used in Chè (Vietnamese pronunciation: [cɛ̂]), a Vietnamese term that refers to any traditional Vietnamese sweet beverage, dessert soup or pudding.


Tremella fuciformis is known to be a parasite of Hypoxylon species. Many of these species were reassigned to a new genus, Annulohypoxylon, in 2005 including its preferred host, Annulohypoxylon archeri, the species routinely used in commercial cultivation. Following its host, fruit bodies are typically found on dead, attached or recently fallen branches of broadleaf trees.
The species is mainly tropical and subtropical, but extends into temperate areas in Asia and North America. It is known throughout South and Central America, the Caribbean, parts of North America, sub-Saharan Africa, southern and eastern Asia, Australia, New Zealand (although this may be an NZ indegineous species), and the Pacific Islands.


The Texas cichlid (Herichthys cyanoguttatus, formerly Cichlasoma cyanoguttatum)  is a freshwater fish of the cichlid family. This is the only cichlid species that is native to the United States.  The fish, also known as Rio Grande cichlid, originates from the lower Rio Grande drainage in Texas near Brownsville and Northeastern Mexico.
Herichthys cyanoguttatus can grow to be over 13 in (33 cm) and are differentiated by their distinctive characteristics and specific habitat needs.  This cichlid is known for its cream and turquoise spots. Adult males also develop a nuchal hump on their head. This cichlid also prefers the water temperature to be between  68 and 82 °F (20–28 °C) and are negatively affected by rapid changes in temperature.


The cichlid has an omnivorous diet that consists of vegetable matter or detritus, often feasting on plants, insects, and smaller fish as well as fish eggs. The cichlid, in certain situations, can also be described as an "opportunistic carnivore", feeding on small vertebrates and invertebrates, including small frogs and water snakes.  The cichlid is a "deliberate hunter" and it depends on the camouflage of its skin in order to sneak up on its prey.


The short-beaked echidna (Tachyglossus aculeatus) is one of four living species of echidna and the only member of the genus Tachyglossus. It is covered in fur and spines and has a distinctive snout and a specialized tongue, which it uses to catch its insect prey at a great speed. Like the other extant monotremes, the short-beaked echidna lays eggs; the monotremes are the only living group of mammals to do so.
The short-beaked echidna has extremely strong front limbs and claws, which allow it to burrow quickly with great power. As it needs to be able to survive underground, it has a significant tolerance to high levels of carbon dioxide and low levels of oxygen. It has no weapons or fighting ability but repels predators by curling into a ball and deterring them with its spines. It lacks the ability to sweat and cannot deal with heat well, so it tends to avoid daytime activity in hot weather. It can swim if needed. The snout has mechanoreceptors and electroreceptors that help the echidna to detect its surroundings.
During the Australian winter, it goes into deep torpor and hibernation, reducing its metabolism to save energy. As the temperature increases, it emerges to mate. Female echidnas lay one egg a year and the mating period is the only time the otherwise solitary animals meet one another; the male has no further contact with the female or his offspring after mating. A newborn echidna is the size of a grape but grows rapidly on its mother's milk, which is very rich in nutrients. Baby echidnas eventually grow too large and spiky to stay in the pouch and, around seven weeks after hatching, are expelled from the pouch into the mother's burrow. At around six months of age, they leave the burrow and have no more contact with their mothers.
The species is found throughout Australia, where it is the most widespread native mammal, and in coastal and highland regions of eastern New Guinea, where it is known as the mungwe in the Daribi and Chimbu languages. It is not threatened with extinction, but human activities, such as hunting, habitat destruction, and the introduction of foreign predatory species and parasites, have reduced its distribution in Australia.


The short-beaked echidna was first described by George Shaw in 1792. He named the species Myrmecophaga aculeata, thinking that it might be related to the giant anteater. Since Shaw first described the species, its name has undergone four revisions: from M. aculeata to Ornithorhynchus hystrix, Echidna hystrix, Echidna aculeata and finally, Tachyglossus aculeatus. The name Tachyglossus means "quick tongue", in reference to the speed with which the echidna uses its tongue to catch ants and termites, and aculeatus means "spiny" or "equipped with spines".
The short-beaked echidna is the only member of its genus, sharing the family Tachyglossidae with the extant species of the genus Zaglossus that occur in New Guinea. Zaglossus species, which include the western long-beaked, Sir David's long-beaked and eastern long-beaked echidnas, are all significantly larger than T. aculeatus, and their diets consist mostly of worms and grubs rather than ants and termites. Species of the Tachyglossidae are egg-laying mammals; together with the related family Ornithorhynchidae, they are the only extant monotremes in the world.
The five subspecies of the short-beaked echidna are each found in different geographical locations. The subspecies also differ from one another in their hairiness, spine length and width, and the size of the grooming claws on their hind feet.
T. a. acanthion is found in Northern Territory and Western Australia.
T. a. aculeatus is found in Queensland, New South Wales, South Australia and Victoria.
T. a. lawesii is found in coastal regions and the highlands of New Guinea, and possibly in the rainforests of Northeast Queensland.
T. a. multiaculeatus is found on Kangaroo Island.
T. a. setosus is found on Tasmania and some islands in Bass Strait.
The earliest fossils of the short-beaked echidna date back around 15 million years ago to the Miocene epoch, and the oldest specimens were found in caves in South Australia, often with fossils of the long-beaked echidna from the same period. The ancient short-beaked echidnas are considered to be identical to their contemporary descendants except the ancestors are around 10% smaller. This "post-Pleistocene dwarfing" affects many Australian mammals. Part of the last radiation of monotreme mammals, echidnas are believed to have evolutionally diverged from the platypus around 66 million years ago, between the Cretaceous and Tertiary periods. However, the echidna's pre-Pleistocene heritage has not been traced yet, and the lack of teeth on the fossils found thus far have made it impossible to use dental evidence.
The short-beaked echidna was commonly called the spiny anteater in older books, though this term has fallen out of fashion since the echidna bears no relation to the true anteaters. It has a variety of names in the indigenous languages of the regions where it is found. The Noongar people from southwestern Western Australia call it the nyingarn. In Central Australia southwest of Alice Springs, the Pitjantjatjara term is tjilkamata or tjirili, from the word tjiri for spike of porcupine grass (Triodia irritans). The word can also mean 'slowpoke'. In the Wiradjuri language of Central NSW, it is called wandhayala.
In central Cape York Peninsula, it is called (minha) kekoywa in Pakanh, where minha is a qualifier meaning 'meat' or 'animal', (inh-)ekorak in Uw Oykangand and (inh-)egorag in Uw Olkola, where inh- is a qualifier meaning 'meat' or 'animal'. In the highland regions of southwestern New Guinea, it is known as the mungwe in the Daribi and Chimbu languages. The short-beaked echidna is called miɣu in the Motu language of Papua New Guinea.


The short-beaked echidna is common throughout most of temperate Australia and lowland New Guinea, and is not listed as endangered. In Australia, it remains widespread across a wide range of conditions, including urban outskirts, coastal forests and dry inland areas, and is especially widespread in Tasmania and on Kangaroo Island.
The most common threats to the animal in Australia are motor vehicles and habitat destruction, which have led to localized extinctions. In Australia, the number of short-beaked echidnas has been less affected by land clearance than have some other species, since they do not require a specialized habitat beyond a good supply of ants and termites. As a result, they can survive in cleared land if the cut-down wood is left in the area, as the logs can be used as shelters and sources of insects. However, areas where the land has been completely cleared for single crops that can be mechanically harvested, such as wheat fields, have seen extinctions. Over a decade-long period, around one-third of echidna deaths reported to wildlife authorities in Victoria were due to motor vehicles, and the majority of wounded animals handed in were traffic accident victims. Studies have shown they often choose to traverse drainage culverts under roads, so this is seen as a viable means of reducing deaths on busy roads in rural areas or national parks where the animals are more common.
Despite their spines, they are preyed on by birds of prey, the Tasmanian devil, dingoes, snakes, lizards, goannas, cats, and foxes, although almost all victims are young. Goannas are known for their digging abilities and strong sense of smell, and are believed to have been the main predators of the echidna before the introduction of eutherian mammals. Dingoes are known to kill echidnas by rolling them over onto their backs and attacking their underbellies. A tracking study of a small number of echidnas on Kangaroo Island concluded that goannas and cats were the main predators, although foxes—absent in Kangaroo Island—would be expected to be a major threat.
They were eaten by indigenous Australians and the early European settlers of Australia. Hunting and eating of the echidna in New Guinea has increased over time and caused a decline in the population and distribution areas; it is now believed to have disappeared from highland areas. The killing of echidnas was a taboo in traditional culture, but since the tribespeople have become increasingly Westernised, hunting has increased, and the animals have been more easily tracked down due to the use of dogs.
Infection with the introduced parasitic tapeworm Spirometra erinaceieuropaei is considered fatal for the echidna. This waterborne infection is contracted through sharing drinking areas with infected dogs, foxes, cats, and dingos, which do not die from the parasite. The infection is seen as being more dangerous in drier areas, where more animals are sharing fewer bodies of water, increasing the chance of transmission. The Wildlife Preservation Society of Queensland runs an Australia-wide survey, called Echidna Watch, to monitor the species. Echidnas are also known to be affected by other tapeworms, protozoans and herpes-like viral infections, but little is known of how the infections affect the health of the animals or the populations.
Although it is considered easy to keep echidnas healthy in captivity, breeding is difficult, partly due to the relatively infrequent cycle. In 2009, Perth Zoo managed to breed some captive short-beaked echidnas, and in 2015 the first zoo-born echidnas were successfully bred there. Until 2006, only five zoos have managed to breed short-beaked echidnas, but no captive-bred young have survived to maturity. Of these five institutions, only one in Australia—Sydney's Taronga Zoo—managed to breed echidnas, in 1977. The other four cases occurred in the Northern Hemisphere, two in the United States and the others in western Europe. In these cases, breeding occurred six months out of phase compared to Australia, after the animals had adapted to Northern Hemisphere seasons. The failure of captive breeding programs has conservation implications for the endangered species of echidna from the genus Zaglossus, and to a lesser extent for the short-beaked echidna.


The solitary short-beaked echidna looks for a mate between May and September; the precise timing of the mating season varies with geographic location. In the months before the mating season, the size of the male's testes increases by a factor of three or more before spermatogenesis occurs. Both males and females give off a strong, musky odour during the mating season, by turning their cloacas inside out and wiping them on the ground, secreting a glossy liquid believed to be an aphrodisiac. During courtship—observed for the first time in 1989—males locate and pursue females. Trains of up to 10 males, often with the youngest and smallest male at the end of the queue, may follow a single female in a courtship ritual that may last for up to four weeks; the duration of the courtship period varies with location. During this time, they forage for food together, and the train often changes composition, as some males leave and other join the pursuit. In cooler parts of their range, such as Tasmania, females may mate within a few hours of arousal from hibernation.
Before mating, the male smells the female, paying particular attention to the cloaca. This process can take a few hours, and the female can reject the suitor by rolling herself into a ball. After prodding and sniffing her back, the male is often observed to roll the female onto her side and then assume a similar position himself so the two animals are abdomen to abdomen, having dug a small crater in which to lie. They can lie with heads facing one another, or head to rear. If more than one male is in the vicinity, fighting over the female may occur. Each side of the bilaterally symmetrical, rosette-like, four-headed penis (similar to that of reptiles and 7 centimetres (2.8 in) in length) is used alternately, with the other half being shut down between ejaculations. Sperm bundles of around 100 each appear to confer increased sperm motility, which may provide the potential for sperm competition between males. This process takes between a half and three hours. Each mating results in the production of a single egg, and females are known to mate only once during the breeding season; each mating is successful.
Fertilisation occurs in the oviduct. Gestation takes between 21 and 28 days after copulation, during which time the female constructs a nursery burrow. Following the gestation period, a single, rubbery-skinned egg between 13 and 17 mm (0.5 and 0.7 in) in diameter and 1.5 and 2.0 g (0.053 and 0.071 oz) in weight is laid from her cloaca directly into a small, backward-facing pouch that has developed on her abdomen. The egg is ovoid, leathery, soft, and cream-coloured. Between laying and hatching, some females continue to forage for food, while others dig burrows and rest there until hatching. Ten days after it is laid, the egg hatches within the pouch. The embryo develops an egg tooth during incubation, which it uses to tear open the egg; the tooth disappears soon after hatching.
Hatchlings are about 1.5 centimetres (0.6 in) long and weigh between 0.3 and 0.4 grams (0.011 and 0.014 oz). After hatching, young echidnas are known as "puggles". Although newborns are still semitranslucent and still surrounded by the remains of the egg yolk, and the eyes are still barely developed, they already have well-defined front limbs and digits that allow them to climb on their mothers' bodies. Hatchlings attach themselves to their mothers' milk areolae, specialised patches on the skin that secrete milk—monotremes lack nipples—through about 100–150 pores. The puggles were thought to have imbibed the milk by licking the mother's skin, but they are now thought to feed by sucking the areolae.
They have been observed ingesting large amounts during each feeding period, and mothers may leave them unattended in the burrow for between five and ten days to find food. Studies of captives have shown they can ingest milk once every two or three days and then increase their mass by 20% in one milk-drinking session lasting between one and two hours. Around 40% of the milk weight is converted into body mass, and as such, a high proportion of milk is converted into growth; a correlation with the growth of the puggle and its mother's size has been observed. By the time the puggle is around 200 g (7.1 oz), it is left in the burrow while the mother forages for food, and it reaches around 400 g (14 oz) after around two months. Juveniles are eventually ejected from the pouch at around two to three months of age, because of the continuing growth in the length of their spines. During this period, the young are left in covered burrows while the mothers forage, and the young are often preyed upon. Suckling gradually decreases until juveniles are weaned at about six months of age. The duration of lactation is about 200 days, and the young leave the burrow after 180 to 205 days, usually in January or February, at which time they weigh around 800 and 1,300 g (28 and 46 oz). There is no contact between the mother and young after this point.
The composition of the milk secreted by the mother changes over time. At the moment of birth, the solution is dilute and contains 1.25% fat, 7.85% protein, and 2.85% carbohydrates and minerals. Mature milk has much more concentrated nutrients, with 31.0, 12.4 and 2.8% of the aforementioned nutrients, respectively. Near weaning, the protein level continues to increase; this may be due to the need for keratin synthesis for hair and spines, to provide defences against the cold weather and predators.
The principal carbohydrate components of the milk are fucosyllactose and saialyllactose; it has a high iron content, which gives it a pink colour. The high iron content and low levels of free lactose differ from eutherian mammals. Lactose production is believed to proceed along the same lines as in the platypus.
The age of sexual maturity is uncertain, but may be four to five years. A 12-year field study found the short-beaked echidna reaches sexual maturity between five and 12 years of age, and the frequency of reproduction varies from once every two years to once every six years. In the wild, the short-beaked echidna has an average lifespan of 10 years, though they can live as long as 40. The longest-lived specimen reached 49 years of age in a zoo in Philadelphia. In contrast to other mammals, echidna rates of reproduction and metabolism are lower, and they live longer, as though in slow motion, something caused, at least in part, by their low body temperature, which rarely exceeds 33 °C, even when they are not hibernating.
Like its fellow monotreme the platypus, the short-beaked echidna has a system of multiple sex chromosomes, in which males have four Y chromosomes and five X chromosomes. Males appear to be X₁Y₁X₂Y₂X₃Y₃X₄Y₄X₅ (figure), while females are X₁X₁X₂X₂X₃X₃X₄X₄X₅X₅. Weak identity between chromosomes results in meiotic pairing that yields only two possible genotypes of sperm, X₁X₂X₃X₄X₅ or Y₁Y₂Y₃Y₄, thus preserving this complex system.


Short-beaked echidnas are typically 30 to 45 cm (12 to 18 in) in length, with 75 mm (3 in) of snout, and weigh between 2 and 7 kg (4.4 and 15.4 lb). However, the Tasmanian subspecies, T. a. setosus, is smaller than its Australian mainland counterparts. Because the neck is not externally visible, the head and body appear to merge. The earholes are on either side of the head, with no external pinnae. The eyes are small, about 9 mm (0.4 in) in diameter and at the base of the wedge-shaped snout. The nostrils and the mouth are at the distal end of the snout; the mouth cannot open wider than 5 mm (0.2 in). The body of the short-beaked echidna is, with the exception of the underside, face and legs, covered with cream-coloured spines. The spines, which may be up to 50 mm (2 in) long, are modified hairs, mostly made of keratin. Insulation is provided by fur between the spines, which ranges in colour from honey to a dark reddish-brown and even black; the underside and short tail are also covered in fur.
The echidna's fur may be infested with what is said to be the world's largest flea, Bradiopsylla echidnae, which is about 4 mm (0.16 in) long.
The limbs of the short-beaked echidna are adapted for rapid digging; they are short and have strong claws. Their strong and stout limbs allow it to tear apart large logs and move paving stones, and one has been recorded moving a 13.5-kg (30-lb) stone; a scientist also reported that a captive echidna moved a refrigerator around the room in his home. The power of the limbs is based on strong musculature, particularly around the shoulder and torso areas. The mechanical advantage of its arm is greater than that of humans, as its biceps connects the shoulder to the forearm at a point further down than for humans, and the chunky humerus allows more muscle to form.
The claws on the hind feet are elongated and curved backward to enable cleaning and grooming between the spines. Like the platypus, the echidna has a low body temperature—between 30 and 32 °C (86 and 90 °F)—but, unlike the platypus, which shows no evidence of torpor or hibernation, the body temperature of the echidna may fall as low as 5 °C (41 °F). The echidna does not pant or sweat and normally seeks shelter in hot conditions. Despite their inability to sweat, echidnas still lose water as they exhale. The snout is believed to be crucial in restricting this loss to sustainable levels, through a bony labyrinth that has a refrigerator effect and helps to condense water vapour in the breath. The echidna does not have highly concentrated urine, and around half of the estimated daily water loss of 120 g (4.2 oz) occurs in this manner, while most of the rest is through the skin and respiratory system. Most of this is replenished by its substantial eating of termites—one laboratory study reported ingestion of around 147 g (5.2 oz) a day, most of which was water. This can be supplemented by drinking water, if available, or licking morning dew from flora.
In the Australian autumn and winter, the echidna enters periods of torpor or deep hibernation. Because of its low body temperature, it becomes sluggish in very hot and very cold weather.
Like all monotremes, it has one orifice, the cloaca, for the passage of faeces, urine and reproductive products. The male has internal testes, no external scrotum and a highly unusual penis with four knobs on the tip, which is nearly a quarter of his body length when erect. The gestating female develops a pouch on her underside, where she raises her young.
The musculature of the short-beaked echidna has a number of unusual aspects. The panniculus carnosus, an enormous muscle just beneath the skin, covers the entire body. By contraction of various parts of the panniculus carnosus, the short-beaked echidna can change shape, the most characteristic shape change being achieved by rolling itself into a ball when threatened, so protecting its belly and presenting a defensive array of sharp spines. It has one of the shortest spinal cords of any mammal, extending only as far as the thorax. Whereas the human spinal cord ends at the first or second lumbar vertebra, for the echidna it occurs at the seventh thoracic vertebra. The shorter spinal cord is thought to allow flexibility to enable wrapping into a ball.
The musculature of the face, jaw and tongue is specialised for feeding. The tongue is the animal's sole means of catching prey, and can protrude up to 180 mm (7 in) outside the snout. The snout's shape, resembling a double wedge, gives it a significant mechanical advantage in generating a large moment, so makes it efficient for digging to reach prey or to build a shelter. The tongue is sticky because of the presence of glycoprotein-rich mucus, which both lubricates movement in and out of the snout and helps to catch ants and termites, which adhere to it. The tongue is protruded by contracting circular muscles that change the shape of the tongue and force it forwards and contracting two genioglossal muscles attached to the caudal end of the tongue and to the mandible. The protruded tongue is stiffened by a rapid flow of blood, which allows it to penetrate wood and soil. Retraction requires the contraction of two internal longitudinal muscles, known as the sternoglossi. When the tongue is retracted, the prey is caught on backward-facing keratinous "teeth", located along the roof of the buccal cavity, allowing the animal both to capture and grind food. The tongue moves with great speed, and has been measured to move in and out of the snout 100 times a minute. This is partly achieved through the elasticity of the tongue and the conversion of elastic potential energy into kinetic energy. The tongue is very flexible, particularly at the end, allowing it to bend in U-turns and catch insects attempting to flee in their labyrinthine nests or mounds. The tongue also has an ability to avoid picking up splinters while foraging in logs; the factors behind this ability are unknown. It can eat quickly; a specimen of around 3 kg (6.6 lb) can ingest 200 g (7.1 oz) of termites in 10 minutes.
The echidna's stomach is quite different from other mammals. It is devoid of secretory glands and has a cornified stratified epithelium, which resembles horny skin. Unlike other mammals, which typically have highly acidic stomachs, the echidna has low levels of acidity, almost neutral, with pH in the 6.2–7.4 range. The stomach is elastic, and gastric peristalsis grinds soil particulates and shredded insects together. Digestion occurs in the small intestine, which is around 3.4 m (11 ft) in length. The insect exoskeletons and soil are not digested, being ejected in the waste.
Numerous physiological adaptations aid the lifestyle of the short-beaked echidna. Because the animal burrows, it must tolerate very high levels of carbon dioxide in inspired air, and will voluntarily remain in situations where carbon dioxide concentrations are high. It can dig up to a metre into the ground to retrieve ants or evade predators, and can survive with low oxygen when the area is engulfed by bushfires. The echidna can also dive underwater, which can help it to survive sudden floods. During these situations, the heart rate drops to around 12 beats per minute, around one-fifth of the rate at rest. This process is believed to save oxygen for the heart and brain, which are the most sensitive organs to such a shortage; laboratory testing has revealed the echidna's cardiovascular system is similar to that of the seal. Following the devastation of a bushfire, echidnas can compensate for the lack of food by reducing their daytime body temperature and activity through use of torpor, for a period of up to three weeks.
The echidna's optical system is an uncommon hybrid of both mammalian and reptilian characteristics. The cartilaginous layer beneath the sclera of the eyeball is similar to that of reptiles and avians. The small corneal surface is keratinised and hardened, possibly to protect it from chemicals secreted by prey insects or self-impalement when it rolls itself up, which has been observed. The echidna has the flattest lens of any animal, giving it the longest focal length. This similarity to primates and humans allows it to see distant objects clearly. Unlike placental mammals, including humans, the echidna does not have a ciliary muscle to distort the geometry of the lens and thereby change the focal length and allow objects at different distances to be viewed clearly; the whole eye is believed to distort, so the distance between the lens and retina instead changes to allow focusing. The visual ability of an echidna is not great, and it is not known whether it can perceive colour; however, it can distinguish between black and white, and horizontal and vertical stripes. Eyesight is not a crucial factor in the animal's ability to survive, as blind echidnas are able to live healthily.
Its ears are sensitive to low-frequency sound, which may be ideal for detecting sounds emitted by termites and ants underground. The pinnae are obscured and covered by hair, so predators cannot grab them in an attack, and prey or foreign material cannot enter, although ticks are known to reside there. The macula of the ear is very large compared to other animals, and is used as a gravity sensor to orient the echidna. The large size may be important for burrowing downwards.
The leathery snout is keratinised and covered in mechano- and thermoreceptors, which provide information about the surrounding environment. These nerves protrude through microscopic holes at the end of the snout, which also has mucus glands on the end that act as electroreceptors. Echidnas can detect electric fields of 1.8 mV/cm—1000 times more sensitive than humans—and dig up buried batteries. A series of push rods protrude from the snout. These are columns of flattened, spinous cells, with roughly an average diameter of 50 micrometres and a length of 300 micrometres. The number of push rods per square millimetre of skin is estimated to be 30 to 40. Longitudinal waves are believed to be picked up and transmitted through the rods, acting as mechanical sensors, to allow prey detection.
A well-developed olfactory system may be used to detect mates and prey. A highly sensitive optic nerve has been shown to have visual discrimination and spatial memory comparable to those of a rat. The brain and central nervous system have been extensively studied for evolutionary comparison with placental mammals, particularly with its fellow monotreme, the platypus. The average brain volume is 25 ml, similar to a cat of approximately the same size; while the platypus has a largely smooth brain, the echidna has a heavily folded and fissured, gyrencephalic brain similar to humans, which is seen as a sign of a highly neurologically advanced animal. The cerebral cortex is thinner, and the brain cells are larger and more densely packed and organised in the echidna than the platypus, suggesting evolutionary divergence must have occurred long ago. Almost half of the sensory area in the brain is devoted to the snout and tongue, and the part devoted to smell is relatively large compared to other animals.
The short-beaked echidna has the largest prefrontal cortex relative to body size of any mammal, taking up 50% of the volume in comparison to 29% for humans. This part of the brain in humans is thought to be used for planning and analytical behaviour, leading to debate as to whether the echidna has reasoning and strategising ability. Experiments in a simple maze and with a test on opening a trap door to access food, and the echidna's ability to remember what it has learnt for over a month, has led scientists to conclude its learning ability is similar to that of a cat or a rat.
The echidna shows rapid eye movement during sleep, usually around its thermoneutral temperature of 25 °C, and this effect is suppressed at other temperatures. Its brain has been shown to contain a claustrum similar to that of placental mammals, linking this structure to their common ancestor.


The contiguous wood frog range is from northern Georgia and northeastern Canada in the east to Alaska and southern British Columbia in the west. It is the most widely distributed frog in Alaska. It is also found in the Medicine Bow National Forest.