Babysitting, dive synchrony, and indications of alloparental care in sperm whales
- Cite this article as:
- Whitehead, H. Behav Ecol Sociobiol (1996) 38: 237. doi:10.1007/s002650050238
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Young sperm whales (Physeter macrocephalus) serially accompany different members of their social group at the surface while the majority of the group is foraging at depth. The presence of a nearby larger whale is likely to increase the survival prospects of the young animal. In studies off the Galápagos Islands, first-year calves were less likely to be seen at the surface alone than were larger whales, and groups containing calves showed less synchronous diving behaviour – shorter intervals with no larger whales at the surface – than those without calves. This difference in diving synchrony was not solely the result of behaviour by individuals assumed to be the mothers of calves (as they spent a disproportionate amount of time accompanying them). Thus babysitting in sperm whales seems to be a form of alloparental care. Its benefit may have been an important factor in the evolution of sociality in female sperm whales.