Many animals are able to discriminate between related and
unrelated individuals but how they do so has proven remarkably difficult to
understand. Joachim Frommen and colleagues at the University of Veterinary
Medicine, Vienna have investigated the issue using the three-spined stickleback
and its shoaling preferences as a model system. It turns out that the fish
prefer kin to unrelated conspecifics, regardless of how familiar they are with
individual shoal members. The results indicate that level of familiarity does
not affect the stickleback's ability to recognize kin. Recognition based on
phenotype matching or innate recognition thus seems to be the overruling
mechanism when it comes to choosing members of a peer group.