Temporal-based kinship recognition: A switch in time saves mine.

A wide variety of animals show infanticidal responses to conspecific young but switch to parental responses at a time that their own young could be expected. This widespread, fundamental mechanism of indirect kin recognition has been largely ignored in reviews of kin recognition. The present review examines the behavioural changes seen in both sexes of biparental vertebrates and invertebrates. The sexes may have different qualities of information concerning the timing of the arrival of young, typical with internal fertilization, or may have similar information, typical with external fertilization. Where the information is different the female is usually the one with the more accurate information and is more precise in the timing of behavioural change. Males err on the side of caution concerning harming their own young and become parental earlier than females. Where the information is similar the sexes show similarities in the timing of the change. In all cases studied to date, however, the changes occur prior to the arrival of their own young.