How do scientists study the Tasmanian devil? They count it, follow its disease, learn what it eats and measure what its body can do. As of November 2026, the Tasmanian devil is listed as an endangered species. As of November 2026, a University of Tasmania model estimates that by 2020 the disease occupied more than 90% of the devil's range, local densities had fallen 82% and the total population had fallen to 16,900. As of November 2026, University of Tasmania researchers estimate that the wild devil population peaked at about 53,000 in 1996, less than half of earlier estimates. They forecast that the decline should level off within the next decade, which supports work on helping devils evolve resistance and tolerance. As of November 2026, the Tasmanian government's page says there is no evidence to date that the decline is stopping or that the prevalence of the disease is decreasing.

Counting devils is not simple. In the mid 1990s the total devil population was estimated at 130,000 to 150,000. As of November 2026, spotlight sightings per 10 km route in the core devil range fell 41% between 1992 to 1995 and 2002 to 2005. Researchers combined 35 years of spotlight counts of devils, 10 years before and 25 years after the disease was found, with 21 years of capture-mark-recapture estimates of how many devils live in an area. For one study, researchers gathered 183 estimates of devil density from standard 10-day capture-mark-recapture surveys, each using about 40 traps set over 25 square kilometers. As of November 2026, the Tasmanian government says no one knows how many devils live in the wild, and numbers are thought to be 10,000 to 100,000, because population estimates exist for only a few places chosen for trapping.

Devil facial tumour disease (DFTD) was first detected in 1996, and it is one of only a small number of recorded cancers that can spread from animal to animal like a contagious disease. Gene studies showed the tumour cells express genes typical of Schwann cells, a kind of nerve-supporting cell, or their precursors. Because the tumour cells are all one clone, a group of identical copies, researchers concluded the tumours are not produced by each devil's own body but are transplanted between animals, much like a tissue graft. The disease cells are not rejected by the devil's immune system because the cancer is able to hide from it.

How the tumour cells pass between devils has not been definitively identified, but biting during mating and shared feeding, and the crumbly nature of the facial tumours, suggest the tumour is transplanted by biting. In a University of Tasmania trial, one of five immunised devils did not develop an experimentally induced tumour, and the tumour regressed after immunotherapy in three, suggesting vaccination might work.

The Save the Tasmanian Devil Program, an initiative of the Australian and Tasmanian governments, was set up in 2003 after a national workshop of specialists on the decline of devils due to the facial tumour disease. Australian zoos help the program by breeding devils as an insurance population. As of November 2026, the record shows that devils bred at Healesville Sanctuary in Victoria were released in 2013, 2015 and 2017 to places free of the tumour disease on Maria Island and the Tasman Peninsula.

Researchers say the devil's decline has triggered trophic cascades, which are chain reactions through a food web. It led to a release of invasive feral cats and rodents that were once held in check by this top mammal predator.

University of Tasmania researchers collected 173 hours of video from collars worn by 13 wild devils between 2013 and 2017, and the video-collar study found devils spent more time scavenging than hunting and fed in opportunistic, flexible ways. It highlights the devil's role as a scavenger, not just of large carcasses but in cleaning up small items of carrion in the bush. By eating dead animals, devils help keep the bush clean.

Whisker samples from 91 devils at Wilmot, Tasmania, taken from December 2014 to February 2017, were used to study what devils eat, through the chemical signature in the whisker tissue. A whisker study found that, as weaned devils age, they rely less on small mammals and birds and more on large herbivores. Devils have the skeletal features of pounce-pursuit predators that can make short, fast pursuits, and they appear to forage with a moving search. Devils hunt by a combination of ambush and short pursuits, according to the Australian Government's species profile, but they prefer to eat carrion because they do not have to spend energy hunting it.

A 2005 study estimated bite force from the skulls of 39 kinds of mammals, living and extinct, with the 'dry skull' method. This method links skull dimensions to jaw-muscle size and models the jaw as a simple lever, so the values are theoretical maximums, not measured on living devils. A bite force quotient of 100 was set as average. The devil's quotient in the study was 181. A devil's skull has a strong central ridge with very strong jaw muscles attached, and in very old males the head and neck can make up nearly a quarter of the animal's weight. The Tasmanian government says there is no good measurement of how hard a devil can bite, but that a 10 kg devil has a bite as powerful as a 40 kg dog.

Devils are gorge feeders, and if a devil is not interrupted, it can eat up to 40 per cent of its body weight in 30 minutes. Devils are one of only a few mammalian carnivores with adaptations for eating bone, the other being the hyaenas, and they are an example of convergence between marsupial and placental carnivores.

Devils are dasyurids, in the family Dasyuridae of the order Dasyuromorphia, the group of carnivorous marsupials, and they are most closely related to quolls. Fossil devil species go back to the Miocene epoch, 5 to 23 million years ago. A devil species from about 50,000 to 70,000 years ago, Sarcophilus laniarius, was up to 15% larger and 50% heavier than modern devils.

Fossils show that Tasmanian devils once lived on the Australian mainland, and they disappeared from it about 3,500 years ago. Why devils vanished from the mainland is not known for certain. The Tasmanian government says it was likely due to dry, changing climate, the spread of the dingo and possibly disease, none of which reached Tasmania across Bass Strait. Wild devils live today on the island of Tasmania, which is part of Australia.

People and devils share a long history. A necklace made of 178 pierced devil teeth, found at a burial site about 7,000 years old, shows that Aboriginal Australians interacted with devils. A fact sheet says reconstructions of devil numbers since 1800 found two big declines and increases, but the Australian Government's species profile notes these can be linked to human activities: bounties for the first decline and widespread poison for the second. Tasmania protected devils by law in 1941, and their numbers slowly rose.

Devils are nocturnal, and a devil's hearing is excellent. It seems to be the co-dominant sense along with its sense of smell, which it uses to find food. Devils have many long whiskers, in clumps above the eyes and on the muzzle, that help them forage in the dark and judge their spacing from one another when feeding together. The Tasmanian government counts at least eleven distinct devil sounds, including a snort, a bark, a screech and a sneeze. Devils leave droppings at shared latrine sites, and these act as messages, so a devil can learn which other devils are nearby, including their sex and breeding status.

Tracking shows how far devils go in the dark. A San Diego Zoo Wildlife Alliance library fact sheet, citing a 1990 study, gives individual overlapping home ranges of 4 to 27 square kilometers (1.5 to 10.4 square miles), with males having larger ranges than females. Animal Diversity Web says a devil travels an average of 3.2 km in a night within a relatively small home range, while a devil may travel as far as 16 kilometers (10 miles) in one night looking for food. The same fact sheet, citing a 2008 study, says a tracked male devil was recorded travelling 50 km (31.1 miles) in 48 hours. The Tasmanian government says devils have been 'clocked' running on a flat road at nearly 25 km/h for up to 1 km, and can run at 10 km/h for many kilometres.

A baby devil grows inside its mother for only about 21 days before it is born, and newborn devils are tiny, about the size of a grain of rice. A mother devil carries her babies in a pouch for about four months, and baby devils are called imps. Her pouch has only four teats, so no more than four babies can stay in it. The Tasmanian government says young devils are weaned, no longer drinking their mother's milk, at five to six months old, when they weigh around 3 kg. Devils become adults at about two years old. Young devils usually leave their mothers and live on their own by about December.

Words to know

• clone: identical copy
• convergence: similar evolution
• cascades: chain reactions
• quotient: a score
• bounties: paid rewards
• insurance: safe backup