For the past several millennia, bilbies – a type of Australian marsupial – have shared their environments with dingoes, wild dogs introduced by humans. This has resulted in a hard-wired lesson: dog poo means trouble.
To test whether avoiding dingo droppings, a signal that a predator is in the vicinity, was a learned or inherited response, scientists from the Australian University of New South Wales studied a population of bilbies (Macrotis lagotis) that live in a fenced nature reserve that was cleared of all exotic species 16 years ago.
The researchers first trapped 18 wild bilbies and attached tracking devices before releasing them again. They then set up cameras near the animals’ burrows.
Over the next period, the scientists, led by Lisa Steindler, placed faeces from, variously, dogs, cats and rabbits near the burrows and filmed what happened next. Dog poo was used because it is chemically identical to dingo poo.
The team found that when the bilbies could smell the dog droppings they tended to emerge only partially from their burrows and wait. There was no similar reaction to the faeces of rabbits – which are harmless – or, unfortunately, cats, which represent a direct predatory threat to much of Australia’s wildlife.
The results, says senior author Mike Letnic, say much not only about bilbies, but also about dingoes.
“Our results suggest that dingoes should now be regarded as a native species, because of this innate ability of native prey to recognise dogs as threats,” he explains.
“The study supports the ‘ghosts of predators past’ hypothesis, that a prey’s ability to respond to the odours and images of predators increases with the length of time they have co-existed.
“Bilbies have shared more than 3000 years of evolutionary history with dingoes and dogs, but less than 200 years with cats, which appears to be long enough for them to recognise dog scent.”