The Tasmanian devil (Sarcophilus harrisii) is the world’s largest living carnivorous marsupial, found exclusively on the island state of Tasmania. These stocky, nocturnal scavengers have powerful jaws and a famously ferocious demeanor that serves as a strong defense mechanism. Because of their size and aggressive nature, healthy, adult devils face little risk from other native wildlife. The threats controlling their population today are not traditional predators but a combination of historical ecological shifts and modern, non-natural factors.
Current Natural Predators of Young Devils
While adult devils are largely safe from predation, their young, known as “imps,” are vulnerable after they leave the mother’s pouch. These juvenile devils are small enough to be targeted by larger, specialized hunters native to the Tasmanian landscape. Large birds of prey pose a significant threat, with the Wedge-Tailed Eagle capable of swooping down on young devils active during daylight hours.
Nocturnal predators, such as large owls, also present a danger to the recently weaned imps as they begin to forage at night. The Spotted-Tailed Quoll may occasionally prey on very small young, though quolls more commonly compete with devils for resources. Furthermore, the greatest natural threat often comes from its own species, as larger, dominant devils have been known to consume smaller individuals.
The Historical Apex Predator
For thousands of years, the ecological structure of Tasmania included an apex predator that exerted consistent pressure on the devil population. This role was filled by the Thylacine (Thylacinus cynocephalus), often called the Tasmanian Tiger, before its extinction in the 20th century. As the island’s largest carnivore, the Thylacine likely acted as a natural check on the devil population, especially by preying on juvenile devils.
The presence of the Thylacine meant that the devil was historically a mesopredator, or a mid-level predator. The Thylacine’s disappearance altered the island’s ecosystem dynamics, removing a major source of mortality for the devil. This change allowed the Tasmanian devil to assume the role of the island’s largest carnivorous marsupial.
Non-Natural Mortality Factors
The most significant factors impacting the Tasmanian devil population today are forms of non-natural mortality. These contemporary threats have caused devastating declines, leading to the species being classified as endangered. One major source of death is the high incidence of roadkill, which is exacerbated by the devil’s feeding behavior.
Devils are obligate scavengers, and they are drawn to feed on carrion, which frequently includes other animals killed by vehicles on Tasmania’s roads. Their instinct to scavenge on roadkill, combined with their nocturnal habits, makes them susceptible to being struck by vehicles themselves. This anthropogenic cause accounts for a substantial number of deaths, particularly in areas with high traffic volume.
The single greatest population suppressor, however, is Devil Facial Tumor Disease (DFTD), a transmissible cancer. DFTD spreads between individuals as an infectious, foreign cell line, primarily transmitted through biting during feeding and mating rituals. Since its discovery in 1996, the disease has caused an estimated decline of up to 80% in devil sightings across much of Tasmania.
This disease is characterized by tumors, typically around the mouth and face, that interfere with the animal’s ability to eat. The tumors grow rapidly and are almost universally fatal, causing the affected devil to die from starvation within six months. Scientists have identified two distinct strains, DFT1 and DFT2, both representing a major, ongoing threat to the long-term sustainability of wild devil populations.