It’s not every day you see a "scuba-diving" lizard. That is, unless you’re herpetologist and researcher Lindsey Swierk.
To her knowledge, Swierk is the first (and potentially only) scientist to capture the tiny water anole (Anolis aquaticus) displaying its unique evolutionary strategy to avoid predators. Found in the streams of southern Costa Rica, these tiny scuba divers have created a “scuba tank” method – blowing a giant air bubble around their nose – in order to “breathe” underwater for a record 16 minutes.
“We really don't know too much about this phenomenon yet, which makes it so interesting. I think it's possible that some air pockets are being trapped around the anole's head and throat, and that the inhalation and exhalation of the air bubble allow for some 'trading' of fresh air among these air pockets,” Lindsey Swierk, assistant research professor at the State University of New York, Binghamton, told IFLScience.
Swierk is not sure whether it is the first time an anole has been captured on film doing this but says other animals use similar techniques to stay underwater, namely aquatic insects like the diving beetle.
“Diving beetles will trap air bubbles on their body surfaces using surface tension, and they can breathe the air within these bubbles,” she said. “Spiders use bubbles to stay underwater too. And although star-nosed moles don't use bubbles to respire underwater, they do push bubbles of air in and out to smell underwater, which in my opinion is really awesome.”
Found only in Costa Rica and a small section of Panama, the water anole is a “fascinating species” whose seemingly obscure talent is rooted in survival; diving and remaining underwater for a long time is a strategy to avoid predators.
“These lizards aren't particularly speedy, and taking to the water is a very effective option,” the biologist explained, adding that it was a struggle to capture the lizards because they are so good at diving. “It's easy to 'disappear' to a predator's eye once you hide underwater for a few minutes. I think that any underwater breathing adaptations in water anoles would have arisen to extend the amount of time they can stay in their underwater refuge.”
However, Swierk is quick to caution that her work is in its infancy, and she is simply reporting on a “cool observation”. No study has been published on the topic, although a short natural history observation will be published in the March issue of Herpetological Review. Nevertheless, she believes her work could eventually lead to a better understanding of how evolution has led to multiple solutions to the same problem – how species remain underwater for long periods of time.