ROXBY DOWNS, AUSTRALIA—Katherine Moseby delves into a freezer at this arid mining outpost and pulls out the carcass of a pointy-faced animal the size of a rabbit. It’s a dead greater bilby, or at least what is left of one. She runs a cotton swab along a rip left in the bilby’s soft fur by the teeth of its killer. Later, analysis of DNA from the wound confirms Moseby’s suspicions: This bilby, a threatened species, was slain by a domestic cat.
Over the past 25 years, the ecologist, who works for the University of New South Wales (UNSW) in Sydney, Australia, has examined hundreds of native Australian animals killed by introduced predators, including domestic cats that have gone feral. The native fauna are often easy prey because they haven’t evolved to recognize and dodge the invaders, and medium-size mammals like the bilby have fared worst. Nearly three dozen Australian mammals have gone extinct since Europeans arrived, and although fences and predator eradication efforts have slowed the march toward extinction, Moseby wants to do better, perhaps by accelerating natural selection.
For nearly 5 years, a team she helps lead with Michael Letnic at UNSW and Daniel Blumstein at the University of California, Los Angeles, has been placing bilbies and another threatened species into large fenced plots together with their feline enemies in hopes that, faced with extreme selective pressure, some individuals will learn or adapt to avoid attacks. Results published today suggest the “vaccination” approach has promise: Bilbies exposed to cats in a controlled setting were more likely to survive later, when they were released among feral cats, than those that hadn’t been exposed, they report in the Journal of Applied Ecology.