Anole lizards of the genus ππ―π°ππͺπ΄ are a diverse group of lizards found in the warmer regions of the Americas. Several species have evolved an unusual defence mechanism.
When threatened, the lizards jump into a nearby stream, diving down and remaining submerged until the threat has passed. A recent publication (Boccia π¦π΅ π’π. 2021) demonstrated that these lizards demonstrate a very unusual technique to stay submerged for up to 18 minutes at a time. They βre-breatheβ their air underwater in a manner reminiscent of SCUBA re-breathing equipment.
The lizards cling to rocks or gravel on the bottom of the stream and breathe out an air bubble which sticks to their hydrophobic (water-repelling) scales. They then suck in the air bubble again, breathe, and repeat.
The mechanisms by which this works are not entirely clear at this stage. The air bubble being expelled from the lungs and held underwater may allow carbon dioxide to disperse into the water, or it might allow additional oxygen to be drawn in from either the water or the additional layer of air bubbles stuck to the lizardβs scales.
This behaviour appears to have evolved multiple times via slightly different mechanisms, as all semi-aquatic anoles (not necessarily the species most closely related to one another) display some variant of this behaviour. This is a fantastic example of convergent behavioural evolution in action, and an exciting frontier for future research into the wonders capable by our scaled friends.
For more information watch the YouTube video vignette:
Footage and edits by Dayβs Edge Productions and Lindsey Swierk. Research led by the Mahler Laboratory at the University of Toronto.
Or refer to the original peer-reviewed article published in ππΆπ³π³π¦π―π΅ ππͺπ°ππ°π¨πΊ: https://doi.org/10.1016/j.cub.2021.04.040
Boccia, C. K., Swierk, L., Ayala-Varela, F. P., Boccia, J., Borges, I. L., EstupiΓ±Γ‘n, C. A., … & Mahler, D. L. (2021). Repeated evolution of underwater rebreathing in diving ππ―π°ππͺπ΄ lizards. ππΆπ³π³π¦π―π΅ ππͺπ°ππ°π¨πΊ.
Text by Cora Stobie (Department of Animal and Plant Systematics).
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