Le régime alimentaire de Macaca sylvanus dans différents habitats d’Algérie : I. Régime en chênaie décidue

Abstract

The composition of the diet of a troop of Barbary macaques Macaca sylvanus was studied in Algeria, from February 1983 to October 1984, in a deciduous oak forest (Quercus faginea and Q. afares). Eighty nine percent of the feeding time was devoted annually to feeding on plant material. The troop observed had a basically granivorous and folivorous diet (60 %), lichens and animal prey contributing to 14 and 10.5 percent of the diet respectively. Great seasonal variations were observed : Barbary macaques were mainly carnivorous in spring, feeding on Geometrid moth caterpillars teeming on oak trees leaves ; in summer and autumn they essentially ate acorns, before turning to leaves of Dactylis glomerata and lichens in winter time. Differences in the diet of the three age classes were apparent throughout the year. Young monkeys (0.5 to 3 year old) ate three times as many lichens and twice as many animal prey than adults. Adults (> 4 year old) were more folivorous, while the diet of sub-adults stood in-between. Seventy three plant species, three kinds of lichens, some mushrooms and six kinds of prey were identified in the macaques’diet. However, 74 % of the food items were contributed by four plant species only (Dactylis glomerata, Quercus faginea, Q. afares and Cytisus triflorus), three lichens and the caterpillars. Furthermore, 2 species out of the 8 to 27 consumed each month contributed to more than half of the monthly diet. A little more than fifty per cent of the major food items (acorns, lichens and caterpillars) came from the arboreal layer of the oak forest, 12,4 % from the shrub layer, and 37.1 % from the grass layer. Therefore, half of the food items of this «terrestrial» monkey were dependent upon the presence of tress. Similarly, 44 % of the time spent feeding took place in trees. The variations of the relative levels of arboreality and terrestriality were well adjusted to the relative rates of consumption of different food types. However, significant differences did exist between age classes, since young monkeys spent twice as much time feeding in trees than adults. The adult macaques fed preferably on fallen acorns and on caterpillars moving down to the forest floor to pupate, whereas the young macaques gathered both acorns and caterpillars higher up in trees.