Olfactory Discrimination of Species, Sex, and Sexual Maturity by the Hermann's Tortoise Testudo Hermanni
Many animals obtain reliable information about potential mates, including whether they are conspecific, sexually mature, and healthy or not, mostly from olfactory cues. Previous experiments with snakes and lizards have shown that individuals can recognize conspecifics, sex, mating status, and health condition of potential partners by chemical cues. Using choice experiments, we examined whether both male and female Hermann's Tortoises, Testudo hermanni, can detect and distinguish the odor of conspecifics from that of another species and an odorless control, and are able to discriminate sex and sexual maturity of individuals by chemical cues. We found that both sexes correctly discriminated between their own species and another species' odors, but only males can distinguish sex and sexual maturity of potential mates by olfactory cues. These results indicate a sexual dimorphism in olfactory sensitivity in this species that might be derived from sexual selection and suggest that males and females should rely on different communication channels during social interactions.Abstract

Method of presenting olfactory stimuli to focal tortoises. Swabs containing chemical stimuli are inside the syringes.

Preferences exhibited by male (black bars) and female (blank bars) Hermann's Tortoises toward different olfactory stimuli: (A) conspecific vs. heterospecific odor; (B) odor of same vs. opposite sex; and (C) mature vs. immature individual odor. Error bars represent 1 SE.
Contributor Notes
Section editor: R. Mason.