Breeding behaviour of pilot whales revealed by DNA fingerprinting

Most species of whale spend the majority of their lives well away from land, are capable of migrating over large distances and are difficult to identify individually. However, conservation measures require a detailed understanding of their social structure, breeding behaviour and migration patterns. The advent of DNA fingerprinting permits a systematic investigation of such parameters. In the Faeroe Islands there exists a traditional harvest of long-finned pilot whales (Globicephala melas), in which intact social groups (pods) are captured. This affords a unique opportunity to study genetic relationships within and between pods. We report here on a paternity analysis, using DNA fingerprinting, of mother-fetus pairs and males sampled from complete pods. In addition, a single, highly polymorphic minisatellite locus was used to infer degrees of relatedness between groups of fetuses and females. Taken together, our results suggest that pods consist of closely related adult females and their offspring. Sexually mature males either move frequently between pods or remain in their natal pod but refrain from mating with female relatives. Whichever hypothesis is correct, the data suggest that each male spends only a few months with the female post-mating and individual males often father several fetuses within a pod.