It’s tough being tiny. When you’re an Anole Lizard living in the Caribbean and Latin America, there are all kinds of predators looking to snap you up as a snack.
That’s why the Aquatic Anole has a sneaky trick up its scaly sleeve: When spooked, they promptly belly flop into the nearest waterway and hide down under where they can stay for more than 15 minutes!
Researchers were thrilled to see this new behavior. Were the Anoles holding their breath? Did they develop gills? It turns out that they were doing something even cooler.
They evolved their own rebreathing suit like a scuba diver.
WHAT IS REBREATHING?
Hold up, how does a rebreathing suit work?
Well, when we inhale, our lungs don’t absorb all of the oxygen in our breath. Some of it comes back out when we exhale. A rebreather separates the carbon dioxide, “recycles” the oxygen, and adds more for the next breath.
DON’T BURST THEIR BUBBLE!
When the Aquatic Anole submerges, their special water-repelling skin prevents moisture from sticking. This helps them catch air and form a skin-tight layer, called a plastron.
According to research published by Christopher Boccia and his team in 2021 in Current Biology, the rugose (a kind of wrinkled and bumpy shape) texture of the Anole’s skin helps keep the plastron from dissolving in water. When the Anole exhales, their breath pushes into the skin-tight bubble and creates a little air pocket around their head. When the Anole inhales, they just re-inhale this air supplemented by the air around their skin. Tada, instant mini scuba suit!
What’s more is that the bubble that forms at the Anole’s head may even be able to act like a sort of external gill. According to a National Geographic interview with Roger Seymour— a biologist from the University of Adelaide — and Christopher K. Boccia, it may also be possible that the carbon dioxide and oxygen exchange between the head bubbles, keeping the air fresh.
OTHER ASPIRING DIVERS
The Anolis aquaticus isn’t the only Anole that rebreathes while diving. Boccia’s research in 2021 also found that the Stream Anole (Anolis oxylophus), Lynch’s Anole (Anolis lynchi), Barker’s Anole (Anolis barkeri), and Rueda’s Anole (Anolis maculigula) could also create this life-sustaining air pocket.
These Lizards are not very closely related and it looks like they adapted this amazing behavior independently and without sharing notes with each other.
MULTI-PURPOSE
According to Douglas Main from National Geographic, researchers say that this built-in rebreather could also help the Anole forage for their aquatic food by helping them dive for longer periods of time.
Newly-studied adaptations like the Aquatic Anole’s plastron just go to show how there’s still so much to discover in nature!
PROTECTION AGAINST EXTINCTION
While the Aquatic Anole isn’t threatened by extinction, its diving cousins are. According to the International Union for Conservation of Nature’s Red List of Threatened Species, the Lvnch’s Anole, Barker’s Anole, and Rueda’s Anole are all threatened by habitat destruction because their homes are being turned into residential areas, livestock ranches, and farmlands. With such talented Lizards under threat, it seems all the more pressing to protect their habitats.
The Aquatic Anole’s skin-tight scuba suit helps them avoid predators and maybe even find food. (Lindsey Swierk)
RED FLAG
Here’s another surprise that the Aquatic Anole keeps tucked away for special occasions: They have a bright red-orange dewlap that they flick out to send messages to other Anoles!
According to Lindsey Swierk, a biologist at Binghamton University in New York, the dewlap can be used to make large males look bigger at a distance.
Aside from the size, the color matters, too. Anoles who had redder dewlaps had heads that hinted at a stronger bite. Looks like a red flag that you should be wary of!
