Not so naïve: endangered mammal responds to olfactory cues of an introduced predator after less than 150 years of coexistence

Inability to recognise and/or express effective anti-predator behaviour against novel predators as a result of ontogenetic and/or evolutionary isolation is known as ‘prey naiveté’. Natural selection favours prey species that are able to successfully detect, identify and appropriately respond to predators prior to their attack, increasing their probability of escape and/or avoidance of a predator. However, for many prey species, learning and experience are necessary to develop and perform appropriate anti-predator behaviours. Here, we investigate how a remnant population of bilbies ( Macrotis lagotis ) in south-west Queensland responded to the scents of two predators, native dingoes ( Canis familiaris ) and introduced feral cats ( Felis catus ); a procedural control (rabbits; Oryctolagus cuniculus ); and an experimental control (no scent). Bilbies in Queensland have shared more than 8000 years of co-evolutionary history with dingoes and less than 140 years with feral cats and less than 130 years with rabbits. Bilbies spent the greatest proportion of time investigating and the least amount of time digging when cat and dingo/dog faeces were present. Our results show that wild-living bilbies displayed anti-predator responses towards the olfactory cues of both a long-term predator (dingoes) and an evolutionary novel predator (cats). Our findings suggest that native species can develop anti-predator responses towards introduced predators, providing support for the idea that predator naiveté can be overcome through learning and natural selection as a result of exposure to introduced predators. Significance statement Not so naïve—As a result of lifetime and/or evolutionary isolation from predators, some prey species appear to be naïve towards introduced predators. This is particularly the case in Australia, where native mammalian species appear to be naïve towards recently introduced predators such as the feral cat and European red fox. In a study of wild-living bilbies, we found that 150 years of co-evolutionary experience is enough to develop predator recognition.