Variation in the Timing of Nutritional Weaned Age in Colobus vellerosus

Abstract

The transition between infancy and juvenility occurs once nutritional independence is achieved. Weaning, weaned age, and weaned event are all landmarks during this transition but are ill defined. In this thesis, I reviewed the literature on the transition from infancy to juvenility. I then examined the factors that influenced this transition from nutritional dependence to independence, and survivorship in a wild, folivorous primate. I compiled behavioural records from 83 infants from a population of Colobus vellerosus. Infants were weaned earlier when they lived in a good quality home range. Most weaned events occurred during or prior to peaks in easy to process foods. New juveniles were also more likely to survive when their weaned event coincided with high food availability. These findings suggest that food availability is the most influential factor determining when during the year, and at what age, infants transition to juveniles.