Therapeutic Effects of an Imposed Foraging Task in Disturbed Monkeys*

Abstract

A group of twelve bonnet macaques (Macaca radiata) raised in partial social isolation from birth to adulthood expressed moderate-to-severe behavioral disturbance as a function of their early rearing environments. The range of these behavioral function of their early rearing environments. The range of these behavioral abnormalities in this species are described for the first time. In order to assess the role of the current environment on their behavior, the animals as a group were required to obtain all of their food from a foraging device presenting two levels of difficulty. The therapeutic effect of the imposed foraging task was dependent upon the individual's status in the dominance hierarchy. Low- and high-ranking animals responded positively and became more social (338% above baseline levels) and showed lower levels of specific abnormal behaviors (nearly 75% lower). Mid-ranking animals responded negatively and became less social (89% lower), while their levels of abnormal behavior dramatically increased (200% higher).

The reduction of abnormal behaviors in individually housed rhesus monkeys (Macaca mulatta) with a foraging/grooming board

“…This approach mimics natural situations by paralleling function rather than structure. Foraging behaviors can be quite time-consuming and appear to be instinctual, as defined by James [19611. Several investigators have either hypothesized or actually demonstrated [Rosenblum & Smiley, 1984;Line & Houghton, 19871 that this behavior pattern would be relatively easy to encourage in individually housed macaques. In such studies, foraging behaviors serve to replace undesirable abnormal behaviors occurring in these animals.…”

“…Foraging behaviors among free-ranging animals include search patterns and consumptive processes for fruit, insects, nectar, leaves, and even dirt [Clutton-Brock, 1977;Garber, 1987;Oates, 1987;Marriott, 19881. The goal of increasing the amount of time spent on food processing and consumption by nonhuman primates in the laboratory can be achieved by 1) hiding the food and requiring the animal to search for it [Anderson & Chamove, 1984;Boccia, 1989al; 2) requiring the animal to solve a puzzle or task to gain access to the food [Rosenblum & Smiley, 1984;Line & Houghton, 1987;Gust et al, 1988;Bloom & Cook, 1989;Maki et al, in press]; or 3) giving the food whole to the animal to increase time spent on processing the food to reach the edible parts [Bloomsmith & Maple, 19881. Although some species spend more time engaged in food consumption when the food is presented whole [Lindburg & Smith, 19881, it was hypothesized that reduction of the food size presented to the rhesus monkey might also serve to extend the time spent in foraginglfeeding behaviors.…”

Self-aggression in stumptail macaques: Effects of frustration and social partners

“…Although larger groups or more trios would need to be observed before drawing conclusions about the effects of dominance rank on SA, the present study gives no support to the hypothesis that the most subordinate subject would show most SA. It is interesting to note that in some other studies intermediate-ranking subjects have shown relatively greater behavioural disruption in response to challenging conditions, for example during feeding competition tests (BELZUNG & ANDERSON, 1986;DIEZINGER t~; and in response to a foraging task introduced as an environmental enrichment technique (ROSENBLUM & SMILEY, 1984). This "behavioural vulnerability" of intermediate-ranking animals deserves further study.…”

Straw and forage material ameliorate abnormal behaviors in adult chimpanzees

“…It appears as if this enrichment technique discouraged undesirable behaviors but did not distract from positive, species-appropriate, and presumably pleasant interactions. And whereas a simplistic view of response competition and replacement of one behavioral class with another may be inappropriate [Rosenblum and Smiley, 1984], it is interesting to note that the most prolific regurgitator became the most persistent forager.…”