Uh oh! New approach to saving this species imperiled it

Author: Leah Rosenbaum / Source: Science News for Students

two northern quolls — Scientists moved some northern quolls, such as these, to a predator-free island. After 13 generations, however, the quolls lost their protective fear of predators.

Biologists working to save an endangered kitten-sized Australian marsupial may have put those animals in danger — at least once they return back to their home range.

The species is the endangered northern quoll. Scientists moved some quolls to an island free of the poison toads that had threatened their survival. But a new study finds this appears to have undermined a key survival instinct: fear of those toads.

The quoll spent 13 generations — just 13 years — on the island. But that’s all the time it took to lose their fear response to predators. Researchers described the finding June 5 in Biology Letters.

“Evolution can happen very rapidly” for animals with fast breeding times, says Rick Shine. He’s an evolutionary biologist at the University of Sydney in Australia. He was not involved in the study.

Separating endangered species from predators is a common conservation technique. Zoos sometimes do this by raising animals in captivity. Other groups may raise animals in safely fenced enclosures. Such isolation allows an endangered species to build up its numbers before eventually being released back into the wild.