Preferential Association Among Kin Exhibited in a Population of Atlantic Spotted Dolphins (<em>Stenella frontalis</em>)

Abstract

While it is widely accepted that dolphins form associations with conspecifics based primarily on similarities in age class and reproductive status, perhaps equally important is the investigation into secondary influences such as kinship. Preferential association among kin is well-researched in numerous terrestrial species, but has only recently been investigated in cetaceans. This study brings another species into the body of work being formed on the influence of relatedness on cetacean relationships. The association indices of 26 individuals with known relatives in a population of Atlantic spotted dolphins, Stenella frontalis, were compiled from encounters in the Bahamas from 2002-2006. Analysis demonstrated that there is preferential association among kin in this population. Mean association indices were found to be significantly higher within families than between families, and there was a positive correlation between relatedness and coefficient of association. Also, the effects of social segregation based on sex and age class, which were evident in the sample population as a whole, were absent in kin dyads.