Studying marine mammal social systems

Abstract

Pinnipeds and cetaceans often aggregate, sometimes in their thousands, and on occasion in exceptional densities. Many of these gatherings are not obviously the result of attraction to environmental features. Thus, these are actively maintained groups, not passive aggregations. Groups imply social structure, and social structure can affect ecology, genetics, population biology, and thus issues of conservation and management (Wilson 1975; Sutherland 1998). Hence, both for interest in the social lives of marine mammals, as well as a general understanding of the biology of the animals, their places in ecosystems, and the effects of human activities on them, we need to study social structure. Additionally, because the habitat of marine mammals is so different from that of terrestrial species, an understanding of the social structure of marine mammals provides an important comparative perspective on the forces of mammalian social evolution (Connor et al. 1998). Those who study the social structures of non-humans often use the framework of Hinde (1976) as their conceptual basis. From this perspective, social structure is fundamentally about interactions between individuals. A relationship between two individuals is the content, quality and patterning of their interactions. The social structure of a population is the nature, quality, and patterning of the relationships among its members. A glossary of many of the terms used herein is given at the end of this chapter.