COMPETITION AND COOPERATION BETWEEN LITTER-MATES IN THE SPOTTED HYENA, CROCUTA-CROCUTA

The development of intra-litter competition and cooperation is describ ed in free-living and captive spotted hyaenas. Field data were collect ed on dominance relations in 26 twin litters, and additional behaviour al analyses were performed on different subsets of this group. Intra-l itter dominance relations were assessed on the basis of the direction of aggressive and appeasement behaviour patterns. In all wild litters, one cub clearly dominated the other by the time cubs were observed ab ove-ground, at 2-3 weeks of age. Within the 17 twin litters of mixed s ex, female dominance over male litter-mates was significantly more com mon (N=14) than the reverse (N=3). When males were the dominant litter -mates, they were as aggressive towards their siblings as were females . Rates of intra-litter aggression were highest in the youngest age in terval observed (1-2 months), and dropped significantly the next month . Peak monthly rates of intra-litter aggression correlated significant ly with maternal rank, such that offspring of low-ranking females foug ht more than those of high-ranking females. High levels of intra-litte r cooperation were observed in the context of coalition formation, and youngsters affiliated more with litter-mates than with any other hyae na. In captivity, seven twin and two triplet litters were videotaped d uring the first 2 months of life, and were scored for aggressive inter actions. Results showed that dominance between litter-mates is establi shed as early in development as the first day of life. (C) 1995 The As sociation for the Study of Animal Behaviour