Extended Underwater Time: Lizards Enhance Dive Durations with Air Jacket

Some species of lizards have developed a fascinating adaptation to stay underwater for extended periods by expelling and then re-inhaling bubbles of air. This behavior, initially observed in 2015 during fieldwork in Costa Rica by Lindsey Swierk from Binghamton University, has now been scientifically validated through experiments.

Swierk’s observation of Anolis aquaticus lizards diving into streams and remaining submerged for significant durations led to the discovery of their unique bubble-rebreathing technique. These lizards expel large bubbles from their nostrils underwater, which stay connected to their heads before being breathed in again.

Subsequent research by Swierk and her team revealed that at least 18 species of Anolis lizards employ this bubble-rebreathing strategy, enabling them to stay underwater for up to 18 minutes. Their water-repellent skin, covered by a thin layer of air while submerged, gives them a distinct silvery appearance and allows the bubbles they blow out to remain attached.

In a recent study, Swierk applied an emollient to temporarily alter the lizards’ skin properties, resulting in smaller bubbles being exhaled. The experiment demonstrated that the ability to rebreathe larger bubbles significantly enhances their underwater endurance, likely due to increased oxygen extraction and potential gill-like functions of the bubbles.

This intriguing adaptation mirrors similar mechanisms observed in other underwater creatures like the star-nosed mole and water shrew, although their bubble-rebreathing is believed to serve olfactory rather than respiratory purposes.

Swierk’s findings shed light on the remarkable strategies evolved by these lizards to thrive in their aquatic environments, showcasing the intricate balance between physiological adaptations and survival in the natural world.