Behavioral responses of Barbary macaques (Macaca sylvanus) to variations in environmental conditions in Algeria.

Abstract

In this study, the behavioral responses of Barbary macaques to seasonal and interhabitat variations in resource availability were analyzed over an entire annual cycle. Two groups, one in an evergreen cedar-oak forest (Djurdjura) and the other in a deciduous oak forest (Akfadou), were observed. In this paper, references to data on resource availability published elsewhere are made. Time budget has been studied. Variations in foraging and moving time, in day-range lengths, and in time moving in trees have been considered to estimate the variations in foraging effort and thus energy expenditure. Great monthly variations in foraging effort and other activities were observed in both habitats. In early spring, when resource availabilities were maximal, foraging effort was low while monkeys maximized their feeding time (about 5 h/day). In June, during the peak of the birth season and the rearing period, monkeys minimized their feeding time to the benefit of social interactions (to 1.6-2.7 h/day), whatever the food availability, which was low in Akfadou and high in Djurdjura. In addition, foraging effort remained low in Djurdjura, while it increased in Akfadou. Thus, at the beginning of the dry summer period, monkeys in Akfadou were in a less favorable position than those in Djurdjura. At both sites, in periods of food shortage in summer or in winter, monkeys displayed two different strategies. In the former case, their foraging effort increased, while in the second one it remained relatively low. Whatever the foraging effort, monkeys did not reach the same amount of feeding time as in early spring. In the poorest site of Akfadou, foraging effort was globally greater than in the richest site of Djurdjura, especially for adults. At both sites, adult males spent more time feeding than juveniles and less time in social interactions. Results are discussed according to rearing period, temperatures, and day length constraints. The limits of adaptability to different habitats are considered in light of the demographic parameters.