In late 2024, researchers found a special type of lizard that uses a special bubble they produce around their nose to hide underwater for an extended period of time. The first known vertebrae to use this behavior, called rebreathing.

Many invertebrates, such as certain species of beetles and spiders, are known to use bubbles of air to extend the amount of time they can spend underwater. These bubbles let the air-breathing animals inhale previously exhaled air and get additional oxygen. In 2021, Lindsay Swierk, an assistant research professor at Binghamton University, and her colleagues documented several species of Anolis lizards. One species, the water anole (Anolis aquaticus) is a semi-aquatic lizard that lives near streams in the forest of southern Costa Rica.

But we still don’t know if the bubble on the Water Anolis’ nose actually extends the amount of time they can spend underwater. To test this, the researchers applied a substance that stops bubbles from forming to the skin of one group of lizards, and left the other group as a control group. “Lizard skin is hydrophobic. Typically that allows air to stick to it very tightly to the skin and permits bubbles to form” said Swierk, “But when you cover the skin with an emollient, air no longer sticks to the skin surface, so the bubbles can’t form.”

Swierk’s team then measured how long each group of lizards stayed underwater, and they found that the group with no bubble impairing substance stayed underwater 32% longer on average. According to the team, “This is significant because this is the first experiment that truly shows adaptive significance of bubbles. Rebreathing bubbles allows 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 discovery of this lizard shows that there are so many unique and interesting animals left out there to discover, we just have to look closer.