In a conservation catch-22, efforts to save quolls might endanger them

After 13 generations isolated from predators, the northern quoll lost its fear of them

two northern quolls

UNAFRAID  Conservationists isolated a population of northern quolls, such as these pictured, on a predator-free island to attempt to build back their numbers. After 13 generations, the quolls lost their fear response to predators.

Jonathan Webb

Conservationists are stuck in a catch-22: In trying to save some species, the would-be protectors may be giving the animals an evolutionary disadvantage.