World's smallest scuba-diver: This lizard has a tiny air tank on its nose

Lizards able to form bubbles can stay underwater 32% longer than those without.

In Short

• The exact function of these bubbles remained unclear until now
• It serves as a crucial survival mechanism for water anoles
• Lizards might be using the bubble as a physical gill

In a fascinating discovery, researchers from Binghamton University have uncovered the secret behind a semi-aquatic lizard's ability to breathe underwater.

The water anole, found in Costa Rica's tropical forests, has been observed creating a unique air bubble over its nostrils, allowing it to stay submerged for extended periods.

Dr. Lindsey Swierk, the study's lead researcher, has been investigating this remarkable behaviour.

Previously, she documented these lizards diving underwater and forming air bubbles around their heads when threatened by predators. However, the exact function of these bubbles remained unclear until now.

To determine whether the bubble played a crucial role in underwater respiration, Dr. Swierk conducted an experiment. She applied a substance to some lizards' skin to prevent bubble formation, while leaving a control group untreated.

The results were striking: lizards able to form bubbles could stay underwater 32% longer than those without.

This groundbreaking study, published in Biology Letters, provides the first concrete evidence of the adaptive significance of these rebreathing bubbles.

Dr. Swierk emphasised the importance of this finding, stating, "This is really significant because this is the first experiment that truly shows adaptive significance of bubbles."

The ability to remain submerged for extended periods serves as a crucial survival mechanism for water anoles.

Dr. Swierk likened these lizards to "chicken nuggets of the forest," noting their vulnerability to predators such as birds and snakes. By diving underwater and remaining still, they can effectively evade danger for up to 20 minutes or more.

This discovery opens up new avenues for research, including the possibility that the lizards might be using the bubble as a physical gill, similar to some aquatic insects.

Future studies will explore this hypothesis and its implications for understanding vertebrate adaptations to aquatic environments.

The water anole's unique breathing technique not only provides insights into animal behaviour but also has potential applications in biomimicry and materials science. As Dr. Swierk noted, "Even in animals that seem commonplace – you're always finding new things."