While studying anole lizards in the wild, a group of researchers noticed that some individuals would stay underwater for an unusually long time, even up to 18 minutes in one case. A new study explores this phenomenon and describes an adaptation that may allow a certain type of lizard to “breathe” underwater.
Anoles are a common type of lizard native to tropical regions throughout North, Central, and South America. Some species of anoles are semi-aquatic: they dive underwater to escape predators. Researchers noticed that such diving anoles have large air bubbles located near their nostrils. These air bubbles appear to inflate and deflate as if the lizards are breathing the air inside, a process called re-breathing. They then tested the ability of different types of anoles to stay underwater and found that species known to be semi-aquatic re-breathed more often than terrestrial species. The scientists were able to confirm that the lizards were breathing with the air in the bubble by measuring the amount of oxygen in the bubbles over time.
Re-breathing in anoles is an example of how organisms can evolve complex behaviors that give them an edge in their habitat, but there are still many questions to be explored. For example, in the study, individual lizards displayed large differences in the amount of time they can re-breathe and stay underwater. Is re-breathing a behavior that can improve with practice? Do the lizards dive for reasons other than escaping predators? These questions, and many more, will be the focus of further research.
This study was led by Christopher Boccia, now a PhD student in Biology at Queen’s University in Canada. Corresponding author Dr. Luke Mahler is an Assistant Professor in the Department of Ecology and Evolutionary Biology at the University of Toronto in Canada.
Managing Correspondent: Gemma Johnson
Press Articles: “How some lizards breathe underwater,” ScienceNews, “’Scuba-diving’ lizards use bubble attached to snout to breathe underwater,” EurekAlert!
Original Journal Article: “Repeated evolution of underwater rebreathing in diving Anolis lizards,” Current Biology
Image Credit: Pixabay