Ecology of Vervet Monkeys (Cercopithecus Aethiops) in The Masai‐Amboseli Game Reserve, Kenya

Abstract

Aspects of the ecology of vervet monkeys (Ceropithecus aethiops) are described on the basis of a 21 month field study in East Africa. Analysis of home range utilization demonstrated differences between 4 groups. The smallest group distributed its time over a greater area than did the other groups. For 3 of the groups there appeared to be a strong relationship between group size and the amount of optimal habitat defended. The smallest group defended more optimal habitat than expected. However, this same group spent only 60% of its time in this habitat, whereas the other groups all spent more than 95% of their time in it. The smallest group may have avoided the optimal habitat of its territory as an area of frequent intergroup aggression, and as a result utilized a larger and less productive area. Sleeping—tree preferences of groups and individuals are described and discussed. The minimal distance traveled each day by vervet groups varied from 148 to 2,797 yd. In comparing the mean daily distance covered by 2 groups of equal size it was found that one moved significantly further than the other. More trips were made to permanent water holes between 1300 and 1500 hr and during the dry season than at other times. The frequency of group progressions was greatest at 0700 to 1000 and 1600 to 1900 hr. Study of food habits shows that they were opportunistic omnivores. Elephants were the greatest food competitors of the vervets. The monkeys had at least 16 potential predators. Outside of parks and reserves the greatest predator was the European commercial trapper. Ecological characteristics of vervets and their niche separation from baboons are discussed.