A humble little lizard has developed a clever escape route from predators – it blows a bubble over its nostrils and scuba dives to safety for 20 minutes or more. Now, a biologist has explored exactly how it works.
Anolis aquaticus, or the water anole, is a common lizard species native to Central America. This small, semi-aquatic creature was long known to spend a lot of time in and around water, but just a few years ago scientists discovered their Aquaman superpowers. They can stay underwater for long periods of time, helping them both hunt their favorite insect prey and avoid their own predators.
“Anoles are kind of like the chicken nuggets of the forest. Birds eat them, snakes eat them,” said Lindsey Swierk, author of the study. “So by jumping in the water, they can escape a lot of their predators, and they remain very still underwater. They’re pretty well camouflaged underwater as well, and they just stay underwater until that danger passes. We know that they can stay underwater at least about 20 minutes, but probably longer.”
While underwater, these anoles have been seen to blow bubbles over their nostrils, which sticks closely to their strongly water-repellent skin. But scientists weren’t entirely sure if these bubbles were actively helping the lizards breathe underwater, or were just a by-product of the action. So for the new study, Swierk conducted an experiment.
The researcher applied an emollient (otherwise known as a moisturizer) to the skin of some anoles, which prevents air bubbles from sticking to them. The diving abilities of these lizards that were temporarily unable to form bubbles was then compared to control lizards that could blow them normally. And sure enough, the lizards that could form bubbles were found to stay underwater up to 32% longer than than those without.
“This is really significant because this is the first experiment that truly shows adaptive significance of bubbles,” said Swierk. “Rebreathing bubbles allow lizards to stay underwater longer. Before, we suspected it – we saw a pattern – but we didn’t actually test if it served a functional role.”
The next area of research will investigate whether the anoles use their bubbles as “physical gills,” meaning oxygen diffuses from the water into the bubble that they can then breathe. Insects use this method, but it’s thought that the lizards would be too big.
The research was published in the journal Biology Letters.
Source: Binghamton University
