Long-tailed macaques avoid conflicts during short-term crowding

Crowding has been viewed as a factor eliciting increased levels of aggression and tension in gregarious animals. The present study tested predictions derived from two models, the “density/aggression” model and the “active coping” model, which have been proposed to explain the responses of primates to crowding. In particular, we investigated the responses of a well-established group of long-tailed macaques (Macaca fascicularis) to short-term crowding. The group was periodically crowded for 2-3 hr into a familiar area. Control observations were carried out when the monkeys were in a six times larger enclosure. Data from 42 individuals belonging to different age-sex classes showed that only mild forms of aggression increased under the crowded condition. Crowding also resulted in a decrease in counteraggression, allogrooming, playing, and exploring the environment, while it produced an increase in huddling with companions. The frequency of reconciliation and redirection was not affected by crowding. These findings do not support either of the models but suggest that macaques adopt a “conflict-avoidance strategy” during short-term crowding. They reduce the risk of severe aggression in an environment where interindividual distances are small by simply decreasing the level of activity. Interestingly, however, when aggression occurs during crowding, tension reduction mechanisms such as reconciliation and redirection are used as often as in control conditions. © 1995 Wiley-Liss, Inc.     

Identification of the possible origin of the body target that differentiates play fighting from serious fighting in syrian golden hamsters (Mesocricetus auratus)

Play fighting in the Syrian Golden hamster Mesocricetus auratus can be distinguished from serious fighting by the targets attacked in each case. In play fighting, the animals attack and defend the cheeks and cheek pouches, whereas in serious fighting they attack and defend the rump and lower flanks. Since play typically involves the use of behaviors borrowed from other functional contexts, this paper investigates the origin of the cheek target during play fighting. Comparison of resident-intruder serious fighting with awake and anesthetized intruders does not reveal the cheek to be an inhibited target for serious attack. Similarly, analysis of social investigation and allog-rooming, while revealing the ears to be important targets, do not show the cheeks to be targets in these behaviors. Sniffing, licking, and nibbling of the cheek area appear to occur mainly during sexual encounters by males. This area, seemingly a sexual target, may be the one utilized during play fighting.     

The organization of play fighting in the grasshopper mouse (Onychomys leucogaster): Mixing predatory and sociosexual targets and tactics

The body targets contacted, the type of contact made, and the patterns of defense and counterattack elicited by those attacks are examined in the play fighting of captive male and female pairs of grasshopper mice. The nape was the most frequently contacted body target, irrespective of the type of contact made, be it nosing, allogrooming, biting, or striking with a forepaw. The types of defense varied with both body area contacted and type of attack performed. Based on the topography and pattern of contact, it was concluded that grasshopper mice, as is the case for many other muroid rodents, primarily attack and defend targets otherwise contacted during precopulatory encounters. However, grasshopper mice, which are obligate carnivores, also attack and defend predatory targets, although less frequently than sociosexual targets. Surprisingly, predatory attacks were more likely to be counterattacked with predatory attacks, whereas sociosexual attacks were more likely to be counterattacked with sociosexual attacks. Conspecific aggression involves bites directed at the face, lower flanks, and dorsum. Neither the biting of these areas nor the tactics of attack and defense usually associated with such bites were observed during the juvenile interactions. There were no sex differences in either frequency or patterns of attack and defense in play fighting. The data presented for grasshopper mice shed light on the issue of mixing behavior patterns from multiple functional systems during play. Aggr. Behav. 26:319–334, 2000. © 2000 Wiley‐Liss, Inc.