In a groundbreaking study that sheds new light on the complex interactions between wildlife and wildfire, Australian researchers have discovered that sleepy lizards (Tiliqua rugosus) possess an innate ability to recognize the smell of smoke, a sensory cue that signals the approach of fire. This fascinating discovery not only confirms long-standing anecdotes but also reveals intricate evolutionary adaptations that enable these reptiles to survive in fire-prone environments. As catastrophic wildfire events become increasingly commonplace due to climate change, understanding such behavioral mechanisms in wildlife is critical for conservation and ecosystem management.
The research, recently published in the prestigious journal Biology Letters, represents the first empirical confirmation that sleepy lizards can detect smoke through olfactory sensory pathways and respond by attempting to flee from danger. Remarkably, these lizards do not react to the auditory stimuli of fire, such as crackling sounds, underscoring the specificity and sophistication of their sensory adaptations. The findings emerged from controlled experimental exposures where lizards were subjected to smoke and fire sounds, alongside appropriate control stimuli.
This discovery began with an intriguing observation from zookeepers at a US zoo, who noticed that when their lunches were burnt, captive sleepy lizards exhibited signs of distress while other reptiles remained unaffected. Stimulated by this behavioral anomaly, researchers sought to systematically investigate whether this reaction was innate or learned. Their experiments confirmed that even captive-bred individuals, removed from natural fire contexts, exhibited escape behaviors such as tongue-flicking, pacing, and attempts to flee, indicating that the response is hardwired rather than acquired through experience.
Lead researcher Dr. Chris Jolly of Macquarie University explained, “The ability to detect smoke through olfaction fundamentally alters the way we understand survival strategies in fire-adapted species. Unlike mammals or birds that might rely on vision or hearing, sleepy lizards demonstrate a specialized olfactory response fine-tuned over evolutionary timescales.” This innate behavior likely confers an advantage in fire-prone Australian landscapes where rapid detection and evasion can make the difference between survival and extinction.
The implications of this study reach far beyond a single species or region. The escalating intensity, frequency, and unpredictability of wildfires globally, exacerbated by anthropogenic climate change, threaten biodiversity at unprecedented scales. Understanding which species have evolved early-warning systems and behavioral adaptations to these hazards will be crucial for predicting ecological resilience or vulnerability. Lizards, often overlooked in fire ecology, emerge here as vital sentinels whose sensory ecology deserves further scrutiny.
A critical aspect of the research was the distinction between olfactory and auditory stimuli. By exposing sleepy lizards separately to the scent of smoke and the sound of fire crackling, scientists demonstrated that the lizards exclusively responded to smoke. This reveals a highly selective sensory mechanism, tuning behavioral responses to reliable indicators of fire rather than generalized threat cues. Such precision prevents unnecessary energy expenditure or stress from false alarms due to non-fire noises.
The underlying neurobiology of this phenomenon might involve highly sensitive chemoreceptors located on the lizards’ tongues and nasal cavities, capable of detecting combustion products such as particulate matter and volatile organic compounds characteristic of smoke. This sensory information triggers a neurological cascade that results in escape behavior. Detailed anatomical and physiological studies will be required to elucidate these pathways and their evolutionary origins.
Moreover, the behavioral repertoire observed—tongue-flicking, pacing, and escape attempts—suggests that sleepy lizards mobilize a coordinated set of actions when confronted with smoke. Tongue-flicking, a known mechanism for environmental chemical sampling in squamates, likely serves to intensify detection sensitivity. Pacing and escape behaviors indicate heightened arousal and the activation of flight responses, providing a glimpse into the lizard’s real-time survival strategies.
The study also highlights the broader evolutionary context in which life in fire-prone regions such as Australia has shaped not only morphology but also sensory systems and behavior. Over millennia, fire cycles have acted as powerful selective forces, driving adaptations that enhance detection and evasion. Sleepy lizards now stand as a model for investigating the co-evolution of sensory ecology and environmental hazards, informing conservation biologists about the complexity of fire-adaptive traits.
Importantly, this research draws attention to the diversity of survival strategies among animals confronted with wildfires. While some species might rely on physical refuges, others evolve sensory-warning mechanisms that allow proactive fleeing. Understanding these variations is critical as changing fire regimes alter habitat structures and the availability of refugia. The loss of such innate responses may have dire consequences for species survival under future fire scenarios.
As fires encroach into previously fire-free environments like rainforests, questions arise about the adaptive capacity of resident species lacking evolutionary exposure to fire. Can they develop or acquire similar detection mechanisms? This study opens avenues for comparative research across taxa and ecosystems, seeking to map the distribution and origins of fire-cue recognition and its role in survival.
The urgent conservation message emerging from this work is clear: to safeguard biodiversity in an era of intensifying wildfire threats, we must deepen our understanding of species-specific behavioral adaptations. Complex fire ecology demands integrative approaches combining sensory biology, behavior, and evolutionary history. The sleepy lizard’s escape from smoke is a poignant reminder of nature’s resilience and the intricate ties between organisms and their ever-changing environment.
The study was conducted by a multidisciplinary team, including Dr. Chris Jolly from Macquarie University and Charles Darwin University, Prof. Dale Nimmo from Charles Sturt University, Dr. Alex Carthey from Macquarie University, Ms. Emma van de Pas from Van Hall Larenstein University of Applied Sciences in the Netherlands, and Prof. Martin Whiting from Macquarie University. Their collaborative work advances our comprehension of animal adaptations to one of the most pressing ecological challenges of our time.
Subject of Research: Animals
Article Title: From anecdote to evidence: experimental validation of fire-cue recognition in Australian sleepy lizards
News Publication Date: 17-Sep-2025
Web References: http://dx.doi.org/10.1098/rsbl.2025.0364
References: Jolly CJ, Nimmo D, Carthey A, van de Pas E, Whiting MJ (2025). From anecdote to evidence: experimental validation of fire-cue recognition in Australian sleepy lizards. Biology Letters. DOI: 10.1098/rsbl.2025.0364
Image Credits: Credit: Matt Clancy
Keywords: sleepy lizard, Tiliqua rugosus, fire ecology, smoke detection, olfactory cues, wildfire survival, animal behavior, Australian reptiles, climate change adaptation, sensory biology
