Why This Tiny Lizard Dives With a Natural Scuba Tank

Water anoles, semiaquatic lizards that are shorter than a pencil, are highly sought-after snacks among predators in Costa Rican and Panamanian rainforests. Preyed upon by snakes, birds, small mammals and larger lizards, the anoles hide in vegetation along the rocky banks of streams. Faced with danger, a lizard dives into the water and produces a bubble behind its nostrils that allows it to remain submerged for up to 20 minutes, and perhaps much longer.

Lindsey Swierk, a behavioral ecologist at Binghamton University in New York, worked with Luke Mahler and Chris Boccia at the University of Toronto and other researchers to document the scuba-diving prowess of water anoles. But the purpose of their underwater antics was unclear.

wasn’t sure whether the adaptation was a function of survival or just a strange side effect of their hydrophobic skin. While water can’t stick to a lizard’s skin, its composition allows air bubbles to form around parts of its body.

But in findings published Wednesday in the journal Biology Letters, Dr. Swierk found that the bubble allowed this little lizard to stay underwater significantly longer than it otherwise could, supporting the hypothesis that it evolved this ability to evade hungry predators.

Water anoles, semiaquatic lizards that are shorter than a pencil, are highly sought-after snacks among predators in Costa Rican and Panamanian rainforests. Preyed upon by snakes, birds, small mammals and larger lizards, the anoles hide in vegetation along the rocky banks of streams. Faced with danger, a lizard dives into the water and produces a bubble behind its nostrils that allows it to remain submerged for up to 20 minutes, and perhaps much longer.

Lindsey Swierk, a behavioral ecologist at Binghamton University in New York, worked with Luke Mahler and Chris Boccia at the University of Toronto and other researchers to document the scuba-diving prowess of water anoles. But the purpose of their underwater antics was unclear.

wasn’t sure whether the adaptation was a function of survival or just a strange side effect of their hydrophobic skin. While water can’t stick to a lizard’s skin, its composition allows air bubbles to form around parts of its body.

But in findings published Wednesday in the journal Biology Letters, Dr. Swierk found that the bubble allowed this little lizard to stay underwater significantly longer than it otherwise could, supporting the hypothesis that it evolved this ability to evade hungry predators.

This little lizard has shown that in a world where it’s constantly on the menu, a tiny self-formed bubble has become its saving grace. “This is a wonderful example of how evolution works to help animals adapt to all sorts of funky environments and come up with really interesting solutions to problems,”