From anecdote to evidence: experimental validation of fire-cue recognition in Australian sleepy lizards

Fire has shaped the evolution of both plants and animals. Animals exposed to fire throughout their evolutionary history are predicted to exhibit behavioural adaptations that enhance survival during fire. Here, we investigated whether Australian sleepy lizards (Tiliqua rugosa), a large skink from fire-prone regions, recognize and respond to cues of fire. Motivated by reports of captive sleepy lizards reacting to smoke, we conducted behavioural trials exposing wild-caught sleepy lizards to the chemosensory (smoke) and auditory (fire sounds) cues of fire. Behavioural analysis revealed that sleepy lizards exhibited increased activity and significantly greater movements in response to smoke than to water vapour. They did not, however, react aversively to auditory cues of fire, suggesting a reliance on chemosensory rather than auditory cues for fire detection. Our findings provide empirical support for the hypothesis that chemosensory cues of fire elicit escape responses in animals from fire-prone regions, suggesting an evolved, likely innate, behavioural adaptation to recognize and respond to fire cues as indicative of a threat. As climate change increases the frequency and intensity of wildfires, understanding how animals perceive and respond to fire will prove crucial for predicting the threat posed by a more fire-prone future.