Energetics of foraging inMacaca fascicularis andPongo pygmaeus and a selective advantage of large body size in the orang-utan
- Cite this article as:
- Wheatley, B.P. Primates (1982) 23: 348. doi:10.1007/BF02381319
- 141 Downloads
Small animals differ from large animals in their relative and absolute metabolic requirements and energetic expenditures. A preliminary study of the behavioral effects of these size dependent variables were investigated in two arboreal, sympatric and frugivorous anthropoid species:Macaca fascicularis andPongo pygmaeus. Data on both species were collected in East Kalimantan, Indonesia during a 20-month field study which focused onM. fascicularis. There are marked size dependent behavioral differences between the two species which show the constraints of large body size.
Existing hypotheses of the selective advantage of large body size in the orang-utan have either overlooked its advantages by describing it as a remnant of Pleistocene terrestriality and predator defense or attributed its advantage to greater access to resources. Contrasts between the energetics of foraging in the monkey and the ape suggest an alternate hypothesis for selection of large body size relating to the increased capacity of large body size to store fat energy and to subsist on lower quality foods in a relatively marked spatial-temporal unpredictable microhabitat of fruiting and flowering trees. Body size and energetics may play an important role in our models of the evolution of behavior and in the evolution of the great apes.