This article was published in Scientific American’s former blog network and reflects the views of the author, not necessarily those of Scientific American
Tasmanian devils (Sarcophilus harrisii) disappeared from mainland Australia centuries ago, probably not long after humans first brought dingoes to the continent. A new plan could bring the infamous, snarling predators back from the island of Tasmania to Oz. That would not only benefit the devils, which are dying out due to a communicable cancer, but also theoretically help control populations of feral cats and foxes that are driving much of the country's other wildlife to extinction.
Conservation biologists have called cats one of the greatest threats to Australia's mammals. The country is home to 15 to 23 million feral cats, which eat about 75 million native animals a year. The Action Plan for Australian Mammals, published earlier this year, predicts that cats could soon wipe out four of five species and threaten 60 more. European red foxes (Vulpes vulpes), meanwhile, have also taken a terrible toll on a wide range of native wildlife, including birds, bilbies, wallabies and turtles.
Reintroducing devils may help to slow this down. A plan is now in the works to release a small group of the animals into the 50,000-hectare Wilsons Promontory National Park in Victoria to balance out the populations of native wildlife and invasive cats and foxes. The park is home to more than 30 mammalian species. None is endangered at present, but that could change—cat populations are on the rise. (Ironically, cats are thriving due in part to efforts to control populations of foxes, which are feline predators.)
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Mammologist and former Macquarie University professor Tim Flannery proposed reintroducing Tasmanian devils 20 years ago in a book called The Future Eaters. Tasmanian devils placed into Australian habitats could eat young foxes and cats while also competing with them for food during key breeding times, thereby reducing their reproductive success, he told the Australian Broadcasting Corp earlier this week. The devils could also compete with the invaders for nest space.
Evidence from Tasmania suggests that this plan might work. Foxes have never successfully colonized Tasmania because they nest on the ground and have a strong odor that the devils easily sniff out, allowing the natives to eat the invaders' young. Cats have the evolutionary advantage—they can nest in trees, which the devils can't climb. That doesn't mean cats are safe from devils, though. Areas with strong Tasmanian devil populations appear to lack large numbers of cats—and where devils have declined due to cancer (Devil Facial Tumor Disease, or DFTD) cat populations have exploded.
Nothing about this plan is foolproof. Although the move may allow time to find a cure for DFTD, the cancer may still devastate devil populations regardless of where they live. And reintroduced devils may not wind up controlling fox and cat populations, says invasive species specialist and University of Sydney professor Rick Shine. "I support releasing Tasmanian devils in mainland Australia,” he told me. “They belong here. We wiped them out and we have the opportunity to release them—and hopefully save them from the tumor disease."
This is all still theoretical. Scientists are likely to try a controlled experiment before any widespread release. No schedule has been announced, but it can't wait too long. DFTD is so bad that some scientists predict Tasmanian devils could be extinct in the wild by 2025. That doesn't leave much of a window to try to make a difference.
Photo by Jon Clark via Flickr. Used under Creative Commons license