Abstract: Cetacean calves routinely swim in echelon position with their mothers and occasionally with other individuals. In August 2002, we observed an adult Atlantic white-sided dolphin (Lagenorhynchus acutus) swimming with two calves in echelon position, one on each side, three times over a 90-min period. Four possible explanations for this behaviour are considered: (1) twins, (2) chance association, (3) alloparental association in the form of “babysitting,” or (4) adoption. We believe that it is unlikely that this behaviour can be explained by chance or twins; therefore, we believe it represents alloparental association. The presence of a dead lactating female in the area five days before the observation lends support for the adoption hypothesis to explain this unusual observation.

Key Words: Atlantic white-sided dolphin, adoption, Lagenorhynchus acutus, calf, alloparental association, babysitting

Document Type: Research article

DOI: 10.1578/AM.30.2.2004.330

Page Numbers: 330-334