Epimeletic behavior in a free-ranging female Risso’s dolphin (Grampus griseus)

Abstract

Here, we describe the epimeletic behavior of an adult Risso’s dolphin towards a deceased newborn calf of the same species across several days with photographs, acoustic monitoring, and video recordings. Boat-based observation surveys were conducted from April 2014 to October 2021 along the southern coast of Galicia (northwest Spain) as part of a longitudinal study on the ecology of cetacean species. On September 21, 2020, an adult Risso’s dolphin was observed carrying a dead newborn calf in coastal waters. This presumed mother was further sighted with her deceased calf on September 23 and 24 (20 km and 40 km from the first observation site, respectively) and with other adult individuals on September 30, probably after having lost or finally abandoned the carcass. The presumed mother supported the corpse for at least 5 days, which may have had potential consequences for the female health. As direct observations are scarce in the wild, this type of report provides valuable information to better document the occurrence of care-giving behavior in highly mobile marine top predators.