Feeding and Ranging in the Agile Gibbon

Abstract

A group of agile gibbons (Hylobates agilis) was studied for 2 years in the Malay Peninsula. The activity budgets and daily activity patterns of the group are described, together with their ranging behaviour. A list of the plant species eaten and estimates of dietary proportions are presented. Seasonal changes in diet and ranging behaviour are investigated.

Use of the Forest Canopy by the Agile Gibbon

“…The study was conducted at Sungai Dal, West Malaysia (4° 4 5 'N; 100° 5 0 'E), described in Gittins [1982]. The main study group, DG1, consisted of an adult male, an adult female, a juvenile male (about 4 years old) and a 1-year-old infant.…”

“…During a 2-year study of the behaviour and ecology of the agile gibbon in Malaya [Gittins, 1978[Gittins, , 1980[Gittins, , 1982Gittins and Raemaekers, 1980], the opportunity was taken to collect detailed data on the posture and forms of locomotion employed in performing different behavioural activities. Be cause of the close inter-relationship between the structure of the substrate supporting an animal and the posture or form of locomotion employed by the animal, the locations of activities within a tree, in terms of the size of supporting substrate were investigated.…”

Temporal Patterns in Primate Leaf Eating: The Possible Role of Leaf Chemistry

“…It is, therefore, advantageous for animals to eat them before resting [2][3][4], (2) Fruits provide readily accessible energy which is used to make up for the animal's energy deficit immediately after sleep or rest. This results in the peak in fruit eating early in the morning [5][6][7].…”

Diurnal Variation in Foraging and Diet in the Wedge-Capped Capuchin Cebus olivaceus

“…A tendency to reliably take ripe fruits in the early morning has been reported in a number of primate species (e.g., gibbons, Chivers [1975]; Raemaekers [1978]; Gittins [1982]; titi monkeys, Kinzey [1977]; squirrel monkeys, Thorington [1967], Thereafter ani mals reliably take more invertebrates (titi and squirrel monkeys) or leaves (gibbons). In capuchins, this same pattern is primarily, but not completely, a consequence of animals taking figs, the most frequently taken item in the diet, in the early morning.…”

“…Diurnal variation in diet might also result from diurnal changes in preferences for different foods, preferences which might reflect the nutritional require ments of animals. After a night without food, the blood sugar of the animals would be expected to be low, and animals should prefer easily digested food (Chivers, 1975;Clutton-Brock, 1977;Raemaekers, 1978;Gittins, 1982]. Ripe fruits are low in protein but high in nonstructural carbohydrates [Hladik et al, 1971;Hladik, 1977;Milton, 1981], which are easily assimilated [Gray and Fogel, 1980], Animals should prefer species that have high harvest rates and high carbohy drate yield per unit time.…”