Abstract: Abstract. Fifteen years of data on natal dispersal age and the context of dispersal for the feral ponies of Assateague Island, Maryland are presented. Ninety-seven per cent of males and 81% of females dispersed from their natal groups by 5 years of age. For animals that left their natal group, average age of dispersal was 20[middle dot]8 months for males and 24[middle dot]6 months for females. Male dispersal age was strongly and significantly correlated with number of peers in the natal group, and males dispersing with peers were significantly older than males dispersing without peers, suggesting that males delayed dispersal when peers were available for interaction. Female dispersal age was not influenced by number of peers, but was correlated with age of first reproduction. Factors not influencing dispersal age in either sex were presence of a younger sibling, maternal band transfers, and maternal age and dominance rank. The relatively high frequency of females failing to disperse from their natal groups is puzzling in light of data showing diminished fecundity in non-dispersing pony mares.

Abstract: The clinical and radiographic progression, and arthroscopic findings for nine young horses (< 1 year of age) with femoropatellar osteochondrosis (OCD) are presented. Horses had a 2 to 12 week history of bilateral (8 horses) or unilateral (1 horse) hindlimb lameness. The most consistent clinical signs included femoropatellar joint distention and bilateral hindlimb lameness. At the onset of clinical signs, radiographic lesions were not present (4 horses) or subtle (5 horses), but were easily identified on radiographs taken 4 to 24 weeks later. Arthroscopic surgery was delayed until radiographic changes became obvious. Surgical findings in 20 femoropatellar joints were most commonly osteochondral “flaps” located on the proximal lateral trochlear ridge of the femur and were larger than had been indicated by the radiographs. Eight horses were being used for their intended purpose, which was racing (3 horses were racing and 3 were in race training), dressage (1 horse) or pleasure riding (1 horse). One horse required a second surgery when similar lesions developed on the opposite stifle, and was euthanatized 2 months later because of persistent lameness. One clinical signs are observed, osteochondrosis lesions of the distal femur can progress in foals younger than 9 months of age and the full extent of the radiographic lesion may take several weeks to develop.

Abstract: This book examines conflict as a normal and recurrent feature of primate social life, emphasizing that the study of aggression and social conflict is important to understanding the basic processes that contribute to social order. The authors go well beyond the usual view which tends to equate social conflict with fights over food, mates, or social supremacy, and analyze the diverse manifestations and significance of conflict in a variety of case studies. Contributors are scientists with field and laboratory experience in anthropology, behavioral endocrinology, ethology, and psychology. Utilizing the growing body of research on life-span development in primatology, the authors offer more extensive analyses of the complexity of primate social relationships.
“I like the idea of social conflict as opposed to aggression as such. Too much of the focus on conflict has been on aggressive behavior, which is probably the most striking behavior observed in the field. The fact that conflict does not lead to aggression in all cases, that conflict is generally followed by some sort of reconciliation, and the consequences for fitness and future social life are important topics with respect to non-human primate society that should have considerable relevance to thinking about human social conflict.” -- Charles T. Snowdon, University of Wisconsin, Madison
William A. Mason is Research Scientist at the California Regional Primate Research Center and Professor Emeritus of Psychology at the University of California. Sally P. Mendoza is Associate Professor of Psychology and Research Scientist at the California Regional Primate Research Center.
1. Primate Social Conflict: An Overview of Sources, Forms, and Consequences
William A. Mason and Sally P. Mendoza
2. The Nature of Social Conflict: A Psycho-Ethological Perspective
William A. Mason
3. The Evolution of Social Conflict among Female Primates
Joan B. Silk
4. Social Conflict on First Encounters
Sally P. Mendoza
5. Reconciliation among Primates: A Review of Empirical Evidence and Theoretical Issues
Frans B. M. de Waal
6. Social Conflict in Adult Male Relationships in a Free-Ranging Group of Japanese Monkeys
Naosuke Itoigawa
7. The Physiology of Dominance in Stable versus Unstable Social Hierarchies
Robert M. Sapolsky
8. Temperament and Mother-Infant Conflict in Macaques: A Transactional Analysis
William A. Mason, D.D. Long, and Sally P. Mendoza
9. Impact on Foraging Demands on Conflict within Mother-Infants Dyads
Michael W. Andrews, Gayle Sunderland, and Leonard A. Rosenblum
10. Coordination and Conflict in Callicebus Social Groups
Charles R. Menzel
11. Social Conflict in Two Monogamous New World Primates: Pairs and Rivals
Gustl Anzenberger
12. Social Conflict and Reproductive Suppression in Marmoset and Tamarin Monkeys
David H. Abbott
13. Biological Antecedents of Human Aggression
Lionel Tiger
14. Conflict as a Constructive Force in Social Life
David M. Lyons
Index

Abstract: Four experiments were designed to find evidence of observational learning in cattle. The experiments were run on ten experimental heifers, each observing a demonstrator mate performing a task, and on ten control heifers, each observing a non-demonstrator mate. The mates and observers were separated by wire netting in Experiments 1-3, but were in the same room in Experiment 4. The task to be learned was to push a panel to get food into a box. All naive animals were able to observe while their mate performed the task. The observers in Experiments 1 and 4 were Salers heifers that had no prior experience of the testing room; those in Experiment 2 were Salers heifers that were accustomed to the room; those in Experiment 3 were Aubrac or Limousin heifers that had already eaten in the room.
The behaviour of the observers was influenced by their mates: activity at or near the boxes was enhanced by the presence of demonstrators in Experiment 2 (box contacts: 38.0 +/- 16.2 vs. 22.1 +/- 11.9 for experimental and control heifers, respectively; P<0.05), while activity in other parts of the room in Experiment 3 was enhanced when non-demonstrator mates were present (wall sniffing: 5.4 +/- 13.9 vs. 13.9 +/- 13.7; P<0.05). Overall, 26 experimental heifers vs. 19 controls learned the task (P>0.05). The time spent eating was longer when the observer only had visual contact with a demonstrator (Experiment 1: 15.9 +/- 1.6 vs. 11.6 +/- 1.8 min), but was lower when physical contacts with the demonstrator were possible (Experiment 4: 4.6 +/- 8.8 vs. 5.4 +/- 2.2 min; P<0.05).
Ten out of the 11 Limousin heifers learned the task, compared with only three out of the nine Aubrac heifers (P<0.05). The latter spent more time near the door and sniffed the walls more often than the former (2.0 +/- 1.9 vs. 0.4 +/- 0.6 min, P<0.05, and 18.1 +/- 13.4 vs. 2.7 +/- 6.5 min, P<0.01), as though they were trying to flee the situation.
When animals observed a demonstrator, their attention was drawn to stimuli involved in the task but acquisition of knowledge was not greatly improved.