Thermoregulation, habitat quality and the behavioural ecology of gelada baboons ( Theropithecus gelada).

Theropithecus gelada populations living in 3 habitats that differ markedly in vegetation and climate are compared. Habitat and seasonal differences in diet are attributed to the local availability of preferred food types (in particular, grass). Time spent feeding increased with altitude due to a combination of increasing temperature-dependent energy requirements and declining habitat quality. Resting time was used as a reserve store from which additional feeding time could be drawn; social time was conserved. Day journey length increased as a linear function of band size because the increase in food requirement with altitude was exactly offset by a corresponding increase in food density. Although range size was also a linear function of band size, the amount of graze required to support one animal increased with declining ambient temperatures.-from Authors