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If you’ve lived in California for a long enough time and paid close enough attention to our local western fence lizards (Sceloporus occidentalis) scuttling about nearly everywhere, you have probably seen one doing his lizard push-ups, as pictured above. This behavior tends to be most common in the breeding season (spring and summer) because it is done by males to show off the blue coloration of their abdomen to potential partners and competitors. Since the males are so eager to show it off, and female behavior seems to be influenced as a result, we would expect that the coloration signals something. It could be that the blue coloring results from some trait that also makes these lizards stronger (e.g., testosterone levels) and thus more attractive, or perhaps lizards with bluer coloration are more favorable because they have survived despite the vibrance disrupting their camouflage. But the evidence is conflicted as to whether lizards with more of this coloring are actually better-equipped for survival, so for now its exact purpose remains a mystery [1].

Photo by Izzy Kier; Caption by Brady Nichols

Edited by Brady Nichols

References

[1] Langkilde, T., & Boronow, K. E. (2010). Color as a Signal: The Relationship between Coloration and Morphology in Male Eastern Fence Lizards, Sceloporus undulatus. Journal of Herpetology, 44(2), 261–271. https://doi.org/10.1670/08-275.1