Preliminary data on voluntary food sharing in brown capuchin monkeys

Abstract

Spontaneous interactions over fruits and vegetables were observed in a captive group of Cebus apella. The group lacked fully grown males; 3 adult females dominated the remaining 11 individuals, most of which were adolescents and late juveniles. Apart from expressions of interest and unsuccessful attempts to claim food, interactions over food included two types of interindividual food transfer: forced claims (i.e., involuntary transfers) and peaceful sharing. These two categories represented 7.2% and 20.3% of 3,389 observed food interactions, respectively. Sharing of food was subdivided into four categories; the most frequent category was the collection of discarded food items from within reach of the possessor, and the least frequent was active giving of food items by the possessor. The voluntary nature of food transfers was further investigated in an experiment in which two monkeys were placed in adjacent cages with a wire-mesh partition between them. One subject received food; the other did not. Although this setup made it easy for possessors to prevent food transfers, sharing occurred in all 18 tests on different combinations of individuals. In 10 of the tests, possessors were observed to actively push food through the mesh partition to their partner. o 1993 Wiley-Lisa, Inc.

Giving is self-rewarding for monkeys

“…Capuchin monkeys spontaneously share food in both nature and captivity (21,22), and commonly sit next to each other while eating. The present study cannot resolve whether the most critical effect of the prosocial outcome was giving (i.e., producing rewards for the other) or sharing (i.e., engaging in joint food consumption).…”

Begging, Stealing, and Offering: Food Transfer in Nonhuman Primates

“…Whether food transfer involves reciprocal altruism has been specifically investigated in capuchins and tamarins. In captivity, capuchins have been observed to throw food, or push food through wire-mesh partition, into a cage containing other capuchins, and to pass food directly to a group-mate (de Waal et al, 1993;Westergaard et al, 1998;. Experimental studies, in which pairs of female capuchins were separated by a wire mesh and provided with food at different times, indicated that rates of food exchange were similar in both directions within dyads (de Waal, 1997b;.…”

“…An individual looks at, touches or sniffs a food item de Waal et al, 1993; that is in the possession of another individual Perry & Rose, 1994;Wrangham, 1975 Beg An individual exhibits specific posture (eg extended upturned Feistner & Price, 1990; hand) or specific vocalisation while showing interest Attempted transfer An individual attempts to take a portion of a food item Brown et al, 2004 Transfer / provision Any situation in which part or all of the food item changes Brown & Mack, 1978; possession from one individual to another Blurton Jones, 1987 Displacement An individual moves into the feeding position vacated Yamagiwa, 1992; by another individual Resist An individual attempts to prevent transfer by moving or Brown and Mack, 1978; turning away, or by vocal or physical aggression or threat Steal Food transfer occurs despite resistance by the possessor Hoage, 1982;Ruiz-Miranda et al, 1999 Offer A food possessor passes food to another individual or Brown & Mack, 1978; adopts a specific posture and/or vocalises Hoage, 1982;Feistner &Chamove, 1986 Retrieve An individual takes food that another individual has Boesch & Boesch, 1989 dropped on the ground or placed there…”

A proximate perspective on reciprocal altruism

“…Capuchin monkeys spontaneously share food (de Waal et al 1993), so we investigated whether or not these interactions were reciprocal. There are two ways to examine reciprocity.…”