Ranging behavior of woolly spider monkeys,or muriquis,Brachyteles arachnoides

During a 14-month study of one group of woolly spider monkeys, or muriquis (Brachyteles arachnoides),at Fazenda Montes Claros, M. G., Brazil, the group used a home range of 168 ha. Day-range lengths averaged 1283 m and were longer in the wet season than in the dry season. An analysis of travel rates indicated that the group traveled faster on those days when they traveled farther. The availability of large patches of preferred food sources appears to affect daily movement patterns. Intraspecific comparisons, in addition to an apparent expansion of the study group’s home range as their group size has increased, suggest the importance of group size to muriqui range size. Interspecific comparisons between muriquis and sympatric brown howler monkeys suggest that locomotor adaptations are important to understanding species differences in ranging behavior.