Lizards living in habitats recently scorched by wildfire are more attentive to the sound of flames than lizards from nearby unburnt regions, suggesting their fire avoidance is learned rather than innate.
After noticing that many western fence lizards (Sceloporus occidentalis) managed to live through wildfires in the western US that wiped out other animals, at the Spanish National Research Council and her team began investigating how fire may be shaping the behaviour of these reptiles. 鈥淭he species has a high survival rate, so we thought it must be adapting somehow to detect wildfire,鈥� says 脕lvarez-Ruiz.
In 2019, the team visited locations across California, including areas near Los Angeles recently burned by a wildfire, and nearby unburnt wilderness and urban areas. The researchers broadcast four different sounds to the lizards in each habitat: a raging fire, the call of a hungry falcon, the chirps of a non-threatening finch and a bananaquit 鈥� a tropical bird the lizards would never encounter in the wild.
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The researchers watched the lizards鈥� faces through binoculars and counted their glances toward the speaker to measure their attentiveness to each noise.
Lizards that lived in areas touched by wildfires the previous year showed immediate physical agitation and vigilance to the sound of a fire, glancing toward the speaker around 3.2 times per minute. 鈥淭hey were looking around like, 鈥淲here? What happened?鈥欌�� says 脕lvarez-Ruiz. Lizards without fire experience showed less interest, looking at the speaker once per minute.
Those from unburnt areas were twice as alert to the sound of a hungry falcon 鈥� a natural predator of the species 鈥� as those from burnt areas, glancing at the speaker around 1.2 times per minute compared with around 0.6 times for fire survivors. The results suggest lizards that survive fires perceive blazes as an even greater threat than an avian predator.
The work is the first to find that western fence lizards鈥� response to the sound of fire isn鈥檛 biologically hard-wired but learned through experience. 鈥淭hey 鈥榬emember鈥� the sound from the fire that they had to survive,鈥� says 脕lvarez-Ruiz. Similarly, in a , she found that a species of Mediterranean lizard living in recently burned areas would hide if they caught a whiff of wildfire smoke.
As climate change fuels more intense and frequent wildfires in California, species able to learn and adapt to new threats may be able to better persist. 鈥淭here will be an increased risk of fire, so we need to know the survival strategies of animals and the challenges they have to overcome,鈥� says 脕lvarez-Ruiz.
Animal Behaviour
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