How do lizards breathe underwater

Anoles are capable of the amazing feat of underwater breathing. Researchers have discovered that the secret lies in the lizard’s ability to “rebreathe” using bubbles that form around its nose. (Photo: Adrien Chateignier, Flickr, CC BY-NC-ND 2.0)

Researchers have discovered the secret that some anole lizards can stay underwater for up to 20 minutes to escape predators. Earth resident Don Lyman reports that these lizards create air bubbles around their noses and rebreathe them.

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Curwood: We’ll talk about zombie worms and other anomalous lifeforms that appear when whales die in a moment, but first, Don Lyman’s notes on new science.

[SCIENCE NOTE THEME]

Lyman: Anoles (small tropical lizards found primarily in Central and South America and the Caribbean) can dive underwater when threatened. Some anoles can stay underwater for up to 20 minutes, but until recently it was unknown how they were able to stay underwater for so long. To find out, Chris Boccia, a PhD student at Queen’s University in Kingston, Canada, and his colleagues traveled to Costa Rica, where they captured 300 anoles of various species. Some of the experimental anoles were found near rivers, while others were found far from them. Boccia and his research associates then immersed each lizard in a container of river water. While in the water, all anoles appeared to have air bubbles around their noses that they inhaled and exhaled. Lizards found near streams rebreathed bubbles more frequently and stayed underwater longer than their land cousins, Boccia and his colleagues reported in the Journal of Current Biology. One lizard was in the water for 18 minutes, Boccia said.

Scientists are still figuring out how anoles can rely on nasal foam for so long without running out of oxygen. (Photo: Adrien Chateignier, Flickr, CC BY-NC-ND 2.0)

By inserting a tiny oxygen sensor into a bubble around the nose of a submerged lizard, the researchers found that oxygen levels in the bubble slowly decreased as the lizard breathed. By slowing its metabolism, Boccha thinks anoles reduce their need for oxygen, allowing them to stay submerged for several minutes. He also speculates that when oxygen levels in the nasal bubbles drop and carbon dioxide levels rise, the bubbles may gain more oxygen by releasing CO2 and taking dissolved oxygen out of the water. However, further research is needed to confirm that hypothesis. That’s this week’s note on emerging science. I’m Don Lyman.

Link

Read the full study

Get an up-close look at anole’s nose foam