How do scientists study the Tasmanian devil? Scientists use skulls, traps, fossils and video collars to find out. First, the bite. A 2005 study estimated bite force from the skulls of 39 kinds of mammals, living and extinct. It used the 'dry skull' method, which links skull dimensions to jaw-muscle size and models the jaw as a simple lever. 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. 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.

How many devils are there? In the mid 1990s the total devil population was estimated at 130,000 to 150,000. As of November 2026, a newer University of Tasmania study estimates that the wild devil population peaked at about 53,000 in 1996, less than half of earlier estimates. 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. Researchers also combined 35 years of spotlight counts of devils with 21 years of capture-mark-recapture estimates of how many devils live in an area. 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.

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. Why they vanished is not known for certain. The Tasmanian government says it was likely due to dry, changing climate and possibly disease, neither of which reached Tasmania across Bass Strait.

University of Tasmania researchers 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. Devils mostly eat animals that have already died. They prefer to eat carrion because they do not have to spend energy hunting it, but when there is little carrion they will actively hunt. Devils hunt by a combination of ambush and short pursuits, according to the Australian Government's species profile. They hunt live prey such as small mammals and birds.

A devil's skull has a strong central ridge with very strong jaw muscles attached. In very old males the head and neck can make up nearly a quarter of the animal's weight. A devil's big head and heavy teeth are made for crushing bone, and its strong jaws and teeth let it eat nearly all of its food, even bones and fur.

Devils are gorge feeders. 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.

Scientists follow single devils to see how far they go. 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.

Devil facial tumour disease (DFTD) was first detected in 1996. 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. 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 that in diseased areas nearly all sexually mature devils, older than two years, become infected and die of the disease. 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.

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.

Where the disease has been present for several years, females begin to breed at 1 year old instead of 2, which stretches the breeding season from February to July.

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 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. 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 at five to six months old, when they weigh around 3 kg. Devils become adults at about two years old, and young devils usually leave their mothers and live on their own by about December. By eating dead animals, devils help keep the bush clean.

Words to know

• quotient: a score
• scavenging: eating found food
• opportunistic: taking chances
• transmissible: able to spread
• immune: body defence