Abstract and Summary

Visual displays from dog to sheep and acoustic signals from shepherd to dog were analyzed during cooperative herding by human shepherds and Border collie dogs. Unlike other breeds, Border collies herded livestock by approaching it in the stalking posture of a hunting mammalian predator. Data on mature trained and immature untrained Border collies showed that the posture was innate, but was refined by training and experience. Selection for behavioral rather than morphological traits has resulted in stereotyped breed-specific behavior but considerable morphologic variation. The whistle signal repertoires of 14 shepherd/dog herding teams showed a strong correlation between acoustic structures and messages of whistles that intended to stimulate or inhibit the dog's activity toward stock. No correlation was found between acoustic structures used for directional messages. Stimulating signals were short, rapidly repeated notes, with a tendency to rise in frequency. Inhibiting signals were prolonged, descending single notes. Comparable acoustic structures in non-human primate and avian repertoires suggest that the observed correlation is found in similar contexts in those groups. We hypothesize that the appropriate use of these acoustic structures increases the probability of the desired response from the canid receivers.