Is mobbing altruistic or selfish behaviour?

The hypotheses that try to explain mobbing behaviour can be divided into three main classes: altruistic behaviour, parental care and selfish behaviour. To try to distinguish between these hypotheses, I presented 12 Arabian babblers, Turdoides squamiceps, with a snake model, both alone and together with another babbler. Seven components of mobbing were compared in the two situations. Single babblers that were exposed to a snake model carried out mobbing-like behaviour. Mobbing in the absence of an audience or additional participants shows that it is basically a selfish behaviour, and suggests that it is an antipredator behaviour. No difference was found between males and females, and mobbing by two participants together was more intensive than mobbing by each of them on its own. These findings support the prey-predator communication hypothesis. However, the different hypotheses explaining mobbing are not exclusive, and this study does not exclude other hypotheses as secondary explanations. (C) 2003 Published by Elsevier Ltd on behalf of The Association for the Study of Animal Behaviour.