Following and Joining the Informed Individual in Semifree-Ranging Tonkean Macaques (Macaca tonkeana)

The authors investigated whether Tonkean macaques (Macaca tonkeana) can distinguish between 2 group mates with different knowledge and improve their foraging performance. The subjects were 8 young individuals belonging to a group raised in a 2-acre park. The authors carried out 192 tests in which subgroups of 3 individuals were released in a food search […]

Deterioration of planning ability with age in Japanese monkeys (Macaca fuscata)

To investigate the ability of aged monkeys to plan and the effect of aging on this ability, performance in a food retrieval task was assessed in aged and younger Japanese monkeys (Macaca fuscata). In this task, the monkeys had to retrieve food items by selecting from a set of 9 holes, each of which contained […]

Observing Conspecifics Scratching Induces a Contagion of Scratching in Japanese Monkeys (Macaca fuscata)

Although a large number of studies have examined self-directed behaviors (SDBs) such as scratching and self-grooming as nonverbal leakage of negative emotional arousal in humans, few studies have investigated the informative function of SDBs in nonhuman primates. The present study investigated whether viewing another monkey scratching itself elicited negative arousal from conspecific observers in Japanese […]

Depressive behavior in young monkeys subjected to vertical chamber confinement

Young rhesus monkeys were confined in vertical chambers for 6 wk., and their subsequent behavior over a 9-mo. period in both a home-cage and playroom situation was compared with that of like-aged monkeys housed individually or in pairs. In comparison to both control groups, chambered monkeys exhibited excessive amounts of self-clasp and huddle, abnormally low […]

A comparative network analysis of social style in macaques

In group-living species, individuals gain significant advantages from establishing an extensive network of social relationships. This results in complex organizations that are difficult to quantify in a comprehensive manner. In this respect, network analyses are an ideal means to pinpoint the overall properties of social structures, and the place of each individual within these structures. […]

Floating limb behaviors and self-biting are associated in laboratory monkeys

Early descriptions of floating limb behaviors in monkeys were associated with isolation rearing, a practice that ended more than two decades ago. The present authors named various forms of behaviors in which a leg is elevated for no apparent reason: “Floating Limb Suite” (FLS). Floating limb behaviors, identified in laboratory monkeys at the Washington National […]

Temperament in Rhesus, Long-Tailed, and Pigtailed Macaques Varies by Species and Sex

Temperament differs among individuals both within and between species. Evidence suggests that differences in temperament of group members may parallel differences in social behavior among groups or between species. Here, we compared temperament between three closely related species of monkey—rhesus (Macaca mulatta), long-tailed (M. fascicularis), and pigtailed (M. nemestrina) macaques—using cage-front behavioral observations of individually […]