Varying responses to feeding competition in a group of rhesus monkeys (Macaca mulatta)

Abstract

ABSTRACT. The behaviour of members of a group of rhesus monkeys was observed in experimentally created, competitive feeding situations. Socially dominant members of the group tended to start eating before lower-ranking subjects, and generally ate more. Dominants sometimes used aggression to control access to food, but overall, intermediate-ranking monkeys were involved in most agonistic episodes. Non-dominant subjects improved their feeding performance when food was presented in three piles rather than one pile, often by snatching food and consuming it away from the pile. These general patterns were less evident when realistic snake models were placed on some of the food piles. Feeding was disrupted by the presence of snakes, but notably, subordinates risked feeding in these conditions. Piles containing preferred foods and snakes were eaten from, but a low-preference food (carrot) under snakes went untouched by all subjects. The results suggest that group-members evaluate potential risks and benefits of competing for a restricted resource, and that dominance status, while an important factor, is only one element in the equation.

Movements of vervets ( Cercopithecus aethiops ) and patas monkeys ( Erythrocebus patas ) as estimators of food resource size, density, and distribution

“…Foods are more likely to be worth ®ghting over if they cannot be quickly depleted at a given individual feeding site (Post et al 1980;Shopland 1987). It is often presumed that clumped resources are more readily monopolizable or usurpable than dispersed resources (e.g., Southwick 1967;Chalmers 1968;Robinson 1981;Whitten 1983;Monaghan and Metcalfe 1985;Harcourt 1987;Altmann and Muruthi 1988;Boccia et al 1988;Brennan and Anderson 1988;Saito 1996). However, the variable of interest here is probably not clumpiness of foods per se, which is a spatial measure, but rather the depletion times of individual feeding sites, such as those reported here (see also Shopland 1987), which is a temporal measure.…”

The Relative Importance of Size of Food and Interfood Distance in Eliciting Aggression in Captive Rhesus Macaques (Macaca mulatta)

“…Experimental studies designed to test the hypothesis that spatial distribution of food determines the frequency of aggressive competition have consistently failed to reject it [12][13][14][15]. Generally, previous studies have involved varying the distance between foods while maintaining a constant level of overall food abundance.…”

“…In a study of free-ranging brown hares (Lepus europaeus), for example, apple quarters were placed either into one pile with a diameter of 0.5 m or at 1-meter distances over an area of 50 m 2 [13]. Similarly, in a study of captive rhesus macaques (Macaca mulatta), 300 pieces of food (bananas, apples and carrots) were placed either in one pile or in three piles 5 m apart [15]. In both studies, the single pile was meant to represent a clumped distribution of food whereas the alternative was meant to represent a dispersed distribution of food.…”

Influence of food dispersion on feeding activity and social interactions in captive Lophocebus albigena and Cercocebus torquatus torquatus

“…When competition for food was strong (food items in one patch), adult males were observed regularly near trays with food, and thus excluded the other members of the group from gaining access to the food. Rank and food intake were also correlated in female Papio anubis (Barton and Whiten 1993) and in rhesus monkeys (Brennan and Anderson 1988). However, variations in feeding activity during meals were observed in both L. albigena groups and in one C. t. torquatus group: dominant monkeys ate more at the beginning than at the end Letters significance level of Tukey tests (comparisons between subjects), same letter difference is not significant, different letters differences are significant.…”

“…Social interactions among members of groups can be influenced by various factors directly related to food, such as type of food, quantities of food available, spatial distribution of food items (in aggregates or dispersed) and the risks and difficulties incurred when searching for food and eating (Clark and Mangel 1986;Blumstein et al 2002;Schmidt and Hoi 1999;Brennan and Anderson 1988). The impact of the distribution of food on social interactions has been particularly well studied and throws light on the functioning of social groups of primates, showing for instance that the distribution and the behaviour of males and females are strongly linked (Emlen and Oring 1977;Stahl and Kaumanns 2003;Wrangham 1979).…”