Observations of a paternal male with bottlenose dolphin calf (Tursiops truncatus): A case study

Abstract

The rearing and socialization of bottlenose dolphin calves has been largely described as a female role, whether via direct maternal care or allomaternal parenting. Nevertheless, male associations have been observed but are rarely systematically investigated. This case study focused on the opportunistic occurrence of a single bottlenose calf and her associations with the mother, father and two unrelated allomothers in a captive setting. Observations were made postpartum of an adult male and his female calf multiple times per day over the course of the first year of the calf's life, including social (proximity and orientation), aggressive (tail slapping/swatting, threats, jaw popping, chasing) and tactile behaviors. For comparative analyses, data were simultaneously collected on mother-calf and allomother interactions. The results revealed that cohabitation of the paternal male and offspring was prosocial, with negligible levels of aggression (0.03%) even during maternal estrous. The male demonstrated minimal aggressive behaviors toward the calf (e.g., chasing), none of which resulted in injury. Rather, the male's interactions with the calf were considerably affiliative. Although the frequency of interactions between the paternal male and the calf were less than the mother's, father-calf interactions were significantly more frequent than were calf interactions with other dolphins. Over the course of the study, the number of interactions the calf had with mother, father, and allomothers decreased. Overall, these results confirm that care can involve the paternal male, although the relative size of the enclosed setting limits extrapolations to the wild. Nonetheless, these observations suggest that some dolphin fathers may play a role in their calves' social development and rearing. Although additional research on calf socialization is required, the dolphin father in this study established and maintained a social bond with his female calf that was clearly affiliative, and these associations occurred significantly more often than those between the calf and her allomothers.