Problems of kin recognition.

Behavioural ecologists have long assumed that animals discriminate between their kin and non-kin, but paid little attention to how animals recognize their relatives. Although the first papers on kin recognition mechanisms appeared barely 10 years ago, studies now appear frequently in journals of animal behaviour. Initial findings reveal that kin recognition abilities are surprisingly well-distributed throughout the animal kingdom. Yet an understanding of the evolutionary and ecological significance of these abilities demands further analyses of the components of kin recognition mechanisms and the social contexts in which they are expressed. Many controversies and unresolved issues remain, and experimental approaches to these problems promise to continue making kin recognition an important, rapidly moving discipline within behavioural ecology.