Time allocation patterns of lowland woolly monkeys (Lagothrix lagotricha poeppigii) in a neotropical terra firma forest

We investigated the time allocation decisions of lowland woolly monkeys (La gothrix lagotricha poeppigii) in a terra firma forest in eastern Ecuador wh ere they occur sympatrically with 9 other primate species. Woolly monkeys s pent considerable amounts of time searching for and attempting to procure a nimal prey-roughly as much time as they spent consuming plant material: rip e fruits, leaves and flowers. The amount of time spent foraging for animal prey is positively related to the habitat-wide availability of ripe fruits (the predominant component of the woolly monkey diet), and negatively relat ed to both ambient temperature and the abundance of potential prey items in the habitat. Time spent resting showed exactly the opposite pattern with r espect to these ecological variables. These results suggest that woolly mon keys follow an energy-maximizing strategy of food acquisition during times of fruit abundance - focusing on animal foods and perhaps Laying down fat r eserves to utilize when ecological conditions worsen - and follow an energy -minimizing strategy when fruit resources are scarce. Such a strong and sea sonal commitment to animal prey foraging is unique among the ate-line prima tes and is not ubiquitous even among lowland woolly monkeys. We suggest tha t this foraging strategy, and the gr-eater intragroup cohesion that charact erizes some populations of Lagothrix, are both opportunistic responses to r egional differences in habitat quality. Identifying and accounting for such intraspecific variation should be a goal of any analysis of comparative so cioecology.