SOCIAL RELATIONSHIPS AMONG ADULT FEMALE MOUNTAIN GORILLAS

Because gorilla females transfer between breeding units, those in the study groups were probably distantly related and not familiar in immaturity. Apparently as a consequence, affinitive behaviour between most females was rare. However, one mother-daughter pair and one pair of females familiar from immaturity had obviously friendly relationships in adulthood. Further findings were that within dyads, younger partners groomed more, and that young infants markedly affected females' relationships, though oestrus did not. It is suggested that familiarity in immaturity might be necessary for affinity between females in adulthood, and that 'friendly' behaviours, even between relatives, could be essentially selfish. Costs and benefits to females in group living, and the effect of habitat quality on relationships are briefly discussed. © 1979.