The Tasmanian devil (Sarcophilus harrisii) has a complicated history, leading many to believe it is globally extinct, but this is a misconception. While it vanished from the Australian continent millennia ago, the carnivorous marsupial remains alive today, surviving only on the island of Tasmania. The devil is the world’s largest surviving carnivorous marsupial, known for its loud vocalizations and powerful bite. It is currently listed as Endangered by the International Union for Conservation of Nature (IUCN), facing a modern biological crisis that threatens its long-term survival.
The Disappearance from Mainland Australia
The disappearance of the Tasmanian devil from mainland Australia was a prehistoric event that occurred long before European settlement. Based on reliable fossil evidence, the localized extinction took place approximately 3,000 to 3,500 years ago. Scientific analysis of fossil remains estimates the mainland extinction occurred between 3179 and 3227 years Before Present. This timing suggests that multiple environmental pressures converged to eliminate the species from the continent.
The most commonly proposed driver is the arrival and spread of the dingo (Canis lupus dingo), an introduced placental predator that reached the mainland around 4,000 years ago. The dingo was a highly effective hunter and competitor for food resources, likely outcompeting the devil and the thylacine, which also became extinct on the mainland. The devil, being a scavenger and a less specialized predator, struggled to secure resources and avoid predation on its young.
Additional factors, including changes in climate and human activity, also contributed to the devil’s decline. Increased climate variability, particularly the intensification of the El Niño Southern Oscillation (ENSO), may have reduced the availability of carrion, a major food source for the devil. Changes in hunting practices and land use by early human populations placed additional stress on the mainland devil population. The combination of a new apex predator, environmental shifts, and human pressure ultimately led to the devil’s geographic extinction from the continent.
Survival and Isolation in Tasmania
The geographical isolation of Tasmania proved to be the most important factor in the devil’s continued existence. The dingo was unable to cross the Bass Strait, the body of water separating the island from the mainland, meaning the devil never faced its most potent competitor. This natural barrier created a refuge where the species could thrive without the ecological pressure that had wiped out its mainland relatives. For thousands of years, the population remained stable, controlled by natural forces like food availability and competition.
The arrival of European settlers in the 1800s, however, introduced a new threat to the isolated population. Early colonists viewed the devils as nuisances, believing them responsible for killing livestock and poultry. This negative perception led to a bounty scheme introduced as early as 1830, which encouraged trapping and poisoning to eliminate the animals from settled areas.
The persecution continued for over a century, causing a significant decline that nearly led to the species’ collapse on the island. Recognizing the devastating impact, the Tasmanian government officially protected the devil in 1941. This legislative change allowed the population to recover and stabilize over the following decades, ensuring its survival until the end of the 20th century.
The Modern Threat to Tasmanian Devils
The current precarious status of the Tasmanian devil is not due to competition or human hunting but to a unique and devastating biological threat: Devil Facial Tumor Disease (DFTD). First observed in the mid-1990s, DFTD is one of only a few known naturally occurring contagious cancers. Unlike typical cancers that arise from a host’s own cells, DFTD is a transmissible parasitic cancer cell line that spreads between animals.
Transmission occurs when devils engage in aggressive social behaviors like biting during feeding or mating. A cancer cell is physically transferred when an infected devil bites a healthy one, and the foreign tumor cells successfully graft onto the new host. The disease manifests as large, disfiguring tumors that typically form around the mouth and face. These rapidly growing masses interfere with the devil’s ability to eat, leading to starvation within six months.
The high mortality rate and rapid spread of DFTD have caused the wild population to plummet by over 80% in many parts of Tasmania. The species’ classification as Endangered reflects the catastrophic impact of this disease. Conservation efforts now focus on establishing “insurance populations” of healthy, disease-free devils in isolated locations. These efforts include captive breeding programs and predator-proof sanctuaries on the Australian mainland. These safeguarded populations protect the species’ genetic diversity while researchers work on developing a vaccine and identifying naturally disease-resistant devils in the wild.