Intraspecific Aggression Towards Common Bottlenose Dolphin Calves, Northern Gulf of Mexico

Abstract

Infanticide has been widely documented throughout the animal kingdom, and has generally been viewed as an evolved, or adaptive behavior for the perpetrators. Infanticide motivated by increased sexual access to females with calves, or the elimination of potential genetic competition in the form of calf-directed aggression or infanticide, has been proposed for delphinids including killer whales, Indo-Pacific humpback dolphins, Guiana dolphins, and bottlenose dolphins. However, reports of intraspecific aggression towards bottlenose dolphin calves are relatively infrequent, and accounts of confirmed infanticide are rarer still. Reporting instances of intraspecific calf-directed aggression aids researchers to better understand the socio-behavioral context of these aggressive interactions. Here, we report an incident of conspecific aggression towards a calf in a small group of common bottlenose dolphins near Sabine Lake, northwestern Gulf of Mexico. We discuss the behavioral context, and surveyed other researchers to attempt to gauge the prevalence of perceived aggressive interactions among the bottlenose dolphin groups they study in the northern Gulf of Mexico.