Tasmanian Devil

The Tasmanian devil is the largest carnivorous marsupial left in the world, a squat, powerful scavenger with the strongest bite of any living mammal for its size. It is also fighting for survival against one of the strangest threats in nature: a cancer that spreads from animal to animal.

Overview

Devils once lived across Australia but disappeared from the mainland around 3,000 years ago, probably outcompeted by the dingo. They survived on the island of Tasmania, where there are no dingoes, and there they are found in nearly every habitat — dry eucalyptus forest, coastal scrub, farmland, and the fringes of towns.

Physical characteristics

A Tasmanian devil is about the size of a small, stocky dog: black fur, often with a white blaze across the chest or rump, a broad head, thick neck, and a fat-storing tail. It moves with an ungainly, rolling gait but can trot for kilometres and climb.

The head is built around the jaws. Relative to body size, the devil’s bite is the most powerful of any mammal, and its molars can shear through bone. A group at a carcass will eat the entire animal — meat, organs, fur, and skeleton — leaving almost nothing.

Behaviour

Devils are nocturnal and largely solitary while foraging, covering large distances each night sniffing out carrion with an acute sense of smell. But carcasses draw them together, and a shared meal turns into a noisy, theatrical contest of screeches, gapes, and lunges as the animals establish a feeding order. Serious injury is rare; the sound and fury do the work.

Reproduction and life cycle

Devil reproduction is a lottery. A female may give birth to 20 or 30 rice-grain-sized young after a three-week pregnancy, but she has only four teats, so the first four to reach the backward-opening pouch and latch on are the only ones that survive. They stay in the pouch for about four months, then in a den for another few months, becoming independent before their first birthday.

Devil facial tumour disease

In 1996 a photographer captured a devil with facial growths in northeast Tasmania. Those growths turned out to be a transmissible cancer — a lineage of tumour cells that jumps between devils when they bite each other during feeding and mating, taking hold because devils have very low genetic diversity and their immune systems do not recognise the foreign cells as a threat.

The disease is nearly always fatal. It has spread across most of Tasmania and cut the wild devil population by around 80%. A second, independently arisen transmissible cancer has since been found in the same species.

Conservation

The Tasmanian devil is listed as Endangered. The response has been broad:

• Insurance populations of healthy devils in zoos and on quarantined islands, to preserve genetic diversity.
• Monitoring and, in places, active management of wild populations, including removing sick animals.
• Encouraging signs of adaptation — some populations are declining more slowly than models predicted, some devils clear their tumours, and genetic studies show the species is evolving resistance in real time.
• The 2020 mainland reintroduction into a fenced reserve north of Sydney, a first step toward restoring the devil to habitats it lost millennia ago.