Sexual dimorphism in the performance of chemosensory investigatory behaviours by African elephants (Loxodonta africana)

Abstract

AbstractSexual dimorphism in morphology can be accompanied by behavioural differences between the sexes. We examined if investigatory behaviour involving the trunk of African elephants showed sexual dimorphism. Males compete and search for females, but they have a lengthy period of development before they are socially viable mates. Receptive females are relatively rare. We hypothesized that males would display higher rates of chemosensory behaviour following puberty than females. Because males disperse, they were hypothesized to be more likely to contact elephants outside their kinship group. We observed the trunk tip, chemosensory behaviours of African elephants at Addo Elephant National Park, South Africa. For 208 elephants, we found no significant differences in state behaviours around waterholes by age or sex. Yet, older elephants were more likely to investigate the environment and elephant excrement than younger animals. Males were more likely to investigate urine and faeces than females. Only post-puberty animals contacted non-family with males investigating both sexes, while investigations by and to females only involved post-puberty males. Overall, the probability of performing chemosensory behaviours depended on age and sex. Male elephants appear more reliant than females on signals in urine and faeces with ensuing inspections of individuals through trunk tip contacts.