Meeting Abstract
Gopher tortoises are social and have been shown to behaviorally respond to intraspecific chemical cues in their environment, discriminating potential mate-choice cues from other scents. Studies have shown that certain chemicals from chin gland secretions can elicit combat behaviors in male tortoises when placed on inanimate objects. Likewise, other studies of tortoises have shown that olfactory investigation is increased when chin gland secretions are present at burrows and that tortoises are able to recognize familiar from unfamiliar conspecifics. Yet, no study has examined social behaviors, such as head-bobbing, in gopher tortoises towards only a chemical presentation of chin gland secretions. In this study, using a paired design presenting cotton swabs of pooled male gopher tortoise chin gland secretions vs. controls (acetone & strawberry, in two separate experiments), we found that tortoises of both sexes (p=0.68) were 9 times more likely to sniff chin gland secretions than acetone (p=0.0004), and also, performed grouped behaviors (i.e., sniffing, eating, biting, & head bobbing) preferentially towards the chin gland swab (p=0.0003). In the second experiment using chin gland secretions vs. strawberry, we found that tortoises also discriminate between chemical cues through different head bobbing vs. nodding behavior. For example, towards the chin gland treatment, only dominant head bob displays (>10 seconds) were observed similar to courtship (p=0.056), whereas towards the strawberry treatment, only brief (~2 seconds) olfactory nods or head extensions (p=0.03) were observed. Differential head movements suggest discrimination of olfactory signals, in which chin gland cues elicit social awareness but strawberry cues only elicit olfactory awareness.
