Eye-Bulging Behavior in Lizards of the Genus Sceloporus: A Role in Chemical Communication?

We examined eye-bulging behavior in relation to scent-marking and chemosensory behavior in three species of iguanian lizards, Sceloporus jarrovii, S. tristichus, and S. virgatus, in a controlled environment. We studied males of the three species and also females of S. jarrovii and S. tristichus. Overall, the frequency of eye-bulging was positively correlated to the frequency of chin wipes in males, but not females. Chin wipes rarely occurred in the absence of eye-bulging; they were closely associated with the latter and, to some degree, to other chemosensory behavior. Of the three species, S. virgatus exhibited the highest eye-bulging frequency. The possibility of eye-bulging behavior being utilized for chemical communication is discussed.