CONTRASTS BETWEEN MALE RELATIONSHIPS IN WILD GORILLA GROUPS

This paper examines proximate and ontogenetic causes of differences between the relationships of wild gorilla males. Two pairs belonging to different reproductive groups were observed. In both, the mature male was dominant over the younger one. However, in one, the males interacted extremely rarely, while in the other, affinitive behaviour, largely initiated by the younger male, was frequent. Three factors that could have influenced the nature of the relationships are discussed. These are their ontogeny, payoffs to the partners from each other's presence, and the ability of at least one partner to alter any imbalance in payoffs. The importance of understanding such proximate causes of variation within species to consideration of differences between species is emphasised. © 1979 Springer-Verlag.