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Description

The Tasmanian devil is the largest surviving carnivorous marsupial. It has a squat, thick build, with a large head and a tail which is about half its body length. Unusually for a marsupial, its forelegs are slightly longer than its hind legs, and devils can run up to 13 km/h (8.1 mph) for short distances. The fur is usually black, often with irregular white patches on the chest and rump (although approximately 16% of wild devils do not have white patches). These markings suggest that the devil is most active at dawn and dusk, and they are thought to draw biting attacks toward less important areas of the body, as fighting between devils often leads to a concentration of scars in that region. Males are usually larger than females, having an average head and body length of 652 mm (25.7 in), a 258 mm (10.2 in) tail and an average weight of 8 kg (18 lb). Females have an average head and body length of 570 mm (22 in), a 244 mm (9.6 in) tail and an average weight of 6 kg (13 lb), although devils in western Tasmania tend to be smaller. Devils have five long toes on their forefeet, four pointing to the front and one coming out from the side, which gives the devil the ability to hold food. The hind feet have four toes, and the devils have non-retractable claws. The stocky devils have a relatively low centre of mass.

Devils are fully grown at two years of age, and few devils live longer than five years in the wild. Possibly the longest-lived Tasmanian devil recorded was Coolah, a male devil which lived in captivity for more than seven years. Born in January 1997 at the Cincinnati Zoo, Coolah died in May 2004 at the Fort Wayne Children's Zoo. The devil stores body fat in its tail, and healthy devils have fat tails. The tail is largely non-prehensile and is important to its physiology, social behaviour and locomotion. It acts as a counterbalance to aid stability when the devil is moving quickly. An ano-genital scent gland at the base of its tail is used to mark the ground behind the animal with its strong, pungent scent. The male has external testes in a pouch-like structure formed by lateral ventrocrural folds of the abdomen, which partially hides and protects them. The testes are subovoid in shape and the mean dimensions of 30 testes of adult males was 3.17 cm × 2.57 cm (1.25 in × 1.01 in). The female's pouch opens backwards, and is present throughout its life, unlike some other dasyurids.

The Tasmanian devil has the most powerful bite relative to body size of any living mammalian carnivore, with a Bite Force Quotient of 181 and exerting a canine bite force of 553 N (124 lb). The jaw can open to 75–80 degrees, allowing the devil to generate the large amount of power to tear meat and crush bones —sufficient force to allow it to bite through thick metal wire. The power of the jaws is in part due to its comparatively large head. The teeth and jaws of Tasmanian devils resemble those of hyenas, an example of convergent evolution. Dasyurid teeth resemble those of primitive marsupials. Like all dasyurids, the devil has prominent canines and cheek teeth. It has three pairs of lower incisors and four pairs of upper incisors. These are located at the top of the front of the devil's mouth. Like dogs, it has 42 teeth, however, unlike dogs, its teeth are not replaced after birth but grow continuously throughout life at a slow rate. It has a "highly carnivorous dentition and trophic adaptations for bone consumption". The devil has long claws that allow it to dig burrows and seek subterranean food easily and grip prey or mates strongly. The teeth and claw strength allow the devil to attack wombats up to 30 kg (66 lb) in weight. The large neck and forebody that give the devil its strength also cause this strength to be biased towards the front half of the body; the lopsided, awkward, shuffling gait of the devil is attributed to this.

The devil has long whiskers on its face and in clumps on the top of the head. These help the devil locate prey when foraging in the dark, and aid in detecting when other devils are close during feeding. The whiskers can extend from the tip of the chin to the rear of the jaw and can cover the span of its shoulder. Hearing is its dominant sense, and it also has an excellent sense of smell, which has a range of 1 km (0.62 mi). The devil, unlike other marsupials, has a "well-defined, saddle-shaped ectotympanic ". Since devils hunt at night, their vision seems to be strongest in black and white. In these conditions they can detect moving objects readily, but have difficulty seeing stationary objects.