by Greg Mayer

This beats eating and swimming underwater: Lindsey Swierk, of SUNY Binghamton, reports, in the latest issue of Herpetological Review, that Anolis aquaticus can breathe underwater! Here’s a video she posted at Anole Annals:

The lizard, of course, is not breathing water; rather, it is breathing air that is trapped around it’s body, which it then visibly exhales in a bubble, and then “rebreathes”. I could not tell from how far around the body air was being drawn to the nostrils, but it seems to include at least the head. The longest she has seen them stay down is 16 minutes. It has long been noticed that air can be trapped around an anole’s body when it’s placed in water, and I’ve wondered whether that air might enable an anole to float longer or higher in the water (perhaps aiding “occasional transport”). But Lindsey has placed these casual observations on a much firmer basis, and recorded, for the first time to my knowledge, that the lizards are breathing; that’s something I never suspected. She proposes a “scuba tank” explanation for the behavior– that the lizard is getting oxygen from the recycled air.

Many species of anoles, both on the main and on the islands, are semiaquatic; aquaticus occurs in Costa Rica and Panama, and the ones filmed were in southern Costa Rica. These semiaquatic anoles inhabit the vegetation alongside streams, and jump into the water when approached. As Lindsey notes, it is an effective anti-predator behavior. Many times I have seen anoles of these species flee from my approach into the water; I think I may once have seen aquaticus myself, in southern Costa Rica.

h/t: Matthew, Thom Sanger

Swierk, L. 2019. Anolis  aquaticus (= Norops aquaticus)  (Water Anole). Underwater breathing. Herpetological Review 50:134-135. pdf; jump to p. 27