Lizards Utilize Nostril Bubbles for Underwater Breathing to Evade Predators, Researchers Discover

According to researchers, these pencil-long lizards retreat into streams to escape predators, surviving by creating bubbles at their nostrils. Found along rocks and plants near streams and waterfalls in Central and South America, water anoles face threats from birds, snakes, and larger lizards. This dangerous environment necessitates efficient escape strategies.

The lizards employ various techniques to avoid predation. If camouflage fails or they cannot find shelter, they leap into the water. There, they can remain submerged until danger passes. While it was understood that the bubbles formed over their nostrils during dives, their role in aiding underwater survival required further investigation.

"We are aware they can remain immersed for significant periods," stated Dr. Lindsey Swierk, who studies anoles at Binghamton University, New York. "However, we aimed to learn if the bubble serves a functional role in their respiration."

The process begins when water anoles dive; they exhale to create a bubble over their nostrils. Additionally, small bubbles naturally form on the lizard's hydrophobic skin, which merge into the larger bubble. This connection enhances the oxygen supply for the lizards while submerged.

To assess the use of these bubbles for underwater breathing, Swierk conducted experiments where he recorded how long anoles stayed submerged with and without moisturiser. The lubricant inhibited bubble formation.

In the report published in Biology Letters, Swierk noted that water anoles can remain underwater 32% longer when bubbles form normally. "When they cannot create regular rebreathing bubbles, their diving time decreases," he observed. Although the study showed limited dive durations, the lizards can endure approximately 20 minutes underwater in their natural habitats.

Due to intense predation, Swierk humorously refers to these water anoles as "the chicken nuggets of the forest." Upon spotting a predator, their initial reaction is to freeze, trusting their camouflage. If pursued, they aim for a rock crevice. Resorting to diving occurs only when all else fails; this method can lower their body temperature and lead to sluggishness.

"From our perspective as researchers, diving presents the most effective escape method," Swierk explained. "When submerged, the anoles become challenging to detect through the moving water's surface."

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