Scientists use counts, models, whiskers, cameras and genes to study the Tasmanian devil, and the first method is counting. 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. Disease-like signs were first reported in 1996, and by December 2008 the disease was found across more than 60% of Tasmania, at 64 locations. A University of Tasmania model gives a fuller picture. As of November 2026, the model found that local devil densities fell by an average of 76% ten years after the disease arrived, then levelled off, reaching an 82% decline after 23 years. As of November 2026, the model estimates that by 2020 the disease occupied more than 90% of the devil's range and the total population had fallen to 16,900.

Devil facial tumour disease (DFTD) was first detected in 1996, and it is a cancer that is believed to spread from one devil to another through biting. 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, 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. As of November 2026, the Tasmanian government says a second kind of the transmissible cancer, DFTD 2, was first recorded in 2014, and that it began in a male devil.

As of November 2026, surveys that count devils seen at night show about 80 per cent fewer devils across most of Tasmania since the disease appeared.

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. University of Tasmania researchers also collected 173 hours of video from collars worn by 13 wild devils between 2013 and 2017. The video-collar study found devils spent more time scavenging than hunting and fed in opportunistic, flexible ways. It also highlights the devil's role as a scavenger, not just of large carcasses but in cleaning up small items of carrion in the bush. Devils have the skeletal features of pounce-pursuit predators that can make short, fast pursuits, and they appear to forage with a moving search. By eating dead animals, devils help keep the bush clean.

A 2005 study estimated bite force from the skulls of 39 kinds of mammals, living and extinct, with the 'dry skull' method. The values are theoretical maximums, not measured on living devils. A bite force quotient of 100 was set as average, and 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 dasyurids, in the family Dasyuridae of the order Dasyuromorphia, the group of carnivorous marsupials. They are most closely related to quolls, and 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. The Tasmanian government says this was likely due to dry, changing climate, the spread of the dingo and possibly disease. Wild devils live today on the island of Tasmania, which is part of Australia.

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.

In the 1830s bounties were offered for devils, and over the next century devils became very rare. Tasmania protected devils by law in 1941, and their numbers slowly rose.

Devils are nocturnal, and a devil's hearing is excellent, and 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 also leave droppings at shared latrine sites, and these act as messages, and a devil can learn which other devils are nearby, including their sex and breeding status. A devil's wide, threatening-looking yawn shows fear and uncertainty more than anger, and devils make loud growls and screeches when several of them feed together.

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. 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.

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. On average a devil eats about 12 per cent of its body weight a day in the wild, so a big meal could keep it going for about three days.

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.

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, and the Tasmanian government says young devils are weaned at five to six months old, when they weigh around 3 kg. Devils become adults at about two years old. Where the disease has been present for several years, females begin to breed at 1 year old instead of 2. Young devils usually leave their mothers and live on their own by about December.

Words to know

• clone: identical copy
• scavenger: finds dead food
• carrion: dead animals
• bounties: paid rewards
• weaned: off mother's milk
• insurance: safe backup