Abstract: The tendency for agonistic interaction to increase the probability of friendly interaction between social partners has been demonstrated across a range of Old World primates. While research on such post-conflict behavior proceeds into an hypothesis-testing phase, new comparative information must accumulate to provide full phylogenetic perspective on primate social behavior. Data from New World and prosimian primates are yet extremely limited. We studied captive squirrel monkeys (Saimiri sciureus) via post-conflict (PC) and matched control (MC) observations and analyzed results using both the PC-MC and time-rule methods. Former opponents maintaining affiliative relationships soon engaged in friendly interaction following large proportions of agonistic interactions, whereas non-affiliated individuals, including virtually all male-female pairs, reconciled conflicts rarely. Close-proximity approaching and huddling contact constituted the principal modes of post-conflict amicability. Agonistic interactions of relatively high intensity were most likely to be reconciled and most likely to be reconciled via physical contact. High vulnerability of Saimiri to predation may have favored this species' strong inclination to reconcile soon after agonistic interaction. Research on free-living populations of this and other primate species is needed to illuminate similarities and differences across taxa.

Abstract: Dominance hierarchies in horses primarily influence priority access to limited resources of any kind, resulting in predictable contest outcomes that potentially minimize aggressive encounters and associated risk of injury. Levels of aggression in group-kept horses under domestic conditions have been reported to be higher than in their feral counterparts but can often be attributed to suboptimal management. Horse owners often express concerns about the risk of injuries occurring in group-kept horses, but these concerns have not been substantiated by empirical investigations. What has not yet been sufficiently addressed are human safety aspects related to approaching and handling group-kept horses. Given horse's natural tendency to synchronize activity to promote group cohesion, questions remain about how group dynamics influence human-horse interactions. Group dynamics influence a variety of management scenarios, ranging from taking a horse out of its social group to the prospect of humans mimicking the horse's social system by taking a putative leadership role and seeking after an alpha position in the dominance hierarchy to achieve compliance. Yet, there is considerable debate about whether the roles horses attain in their social group are of any relevance in their reactions to humans. This article reviews the empirical data on social dynamics in horses, focusing on dominance and leadership theories and the merits of incorporating those concepts into the human-horse context. This will provide a constructive framework for informed debate and valuable guidance for owners managing group-kept horses and for optimizing human-horse interactions.

Abstract: The maze learning ability of six pony foals that had been weaned at birth was compared to that of six foals reared normally. The foals' learning ability was also compared to their mothers' learning ability at the same task; the correct turn in a single choice point maze. The maze learning test was conducted when the foals were 6 to 8 mo old and after the mothered foals had been weaned. There was no significant difference between the ability of orphaned (weaned at birth) and mothered foals in their ability to learn to turn left (6 +/- .7 and 5.1 +/- .1 trials, respectively) or to learn the reversal, to turn right (6.7 +/- .6 and 6.2 +/- .6 trials, respectively). The orphan foals spent significantly more time in the maze in their first exposure to it than the mothered foals (184 +/- 42 vs 55 +/- 15 s. Mann Whitney U = 7, P less than .05). The mothers of the foals (n = 11) learned to turn left as rapidly as the foals (5.9 +/- .7 trials), but they were slower to learn to turn right (9.8 +/- 1.4 vs 6.4 +/- .4 trials, Mann Whitney U = 33, P less than .05), indicating that the younger horses learned more rapidly. There was no correlation between the trials to criteria of the mare and those of her foal, but there was a significant negative correlation between rank in trials to criteria and age (r = -65, P less than .05) when data from the mare and foal trials were combined. The dominance hierarchy of the mares was determined using a paired feeding test in which two horses competed for one bucket of feed. Although there was no correlation between rank in the hierarchy and maze learning ability, there was a correlation between body weight and rank in the hierarchy (r = .7, P less than .05). This may indicate either that heavier horses are likely to be dominant or that horses high in dominance gain more weight. Maternal deprivation did not appear to seriously retard learning of a simple maze by foals, although the orphans moved more slowly initially. The lack of maternal influence on learning is also reflected in the lack of correlation between the mare's learning ability and that of her foal. Young horses appear to learn more rapidly than older horses.

Abstract: Preferred associate (nearest neighbour) and mutual grooming relationships among mares, in an isolated family band of free-ranging horses (Equus caballus), were studied, and the structural and functional differences between these two relationships were examined. The frequent partners accompanying the mare were not the same in both these relationships (p<0.05) and mares changed their partners during the study period between 1988-1990. Individual horses of similar rank tended to remain closer together in both winter and summer. Aggressive-submissive behaviour was so infrequent during spring that rank determinations could not be made; however, in fall, although rank could be determined, rank was not correlated with nearest neighbour. Three subgroups, based on preferred associate relationships in summer, fall and winter, directly reflected the age and social rank of the mares in the group. Individual horses of higher rank tended to have many partners in winter, while individuals of lower rank had fewer. There was no significant correlation between the frequency of mutual grooming and individual rank. The mutual grooming relationship was strongly influenced by seasonal changes as the relative amount of grazing time per day increased. Thus, the frequency of mutual grooming was lowest in winter and highest in summer. The mutual grooming relationship was based on the bonds between individual horses, which were little influenced by social rank. Lower ranking individuals tended to have a greater variety of grooming partners in summer.