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Edwards, D. H., & Spitzer, N. (2006). 6. Social dominance and serotonin receptor genes in crayfish. Curr Top Dev Biol, 74, 177–199.
Abstract: Gene expression affects social behavior only through changes in the excitabilities of neural circuits that govern the release of the relevant motor programs. In turn, social behavior affects gene expression only through patterns of sensory stimulation that produce significant activation of relevant portions of the nervous system. In crayfish, social interactions between pairs of animals lead to changes in behavior that mark the formation of a dominance hierarchy. Those changes in behavior result from changes in the excitability of specific neural circuits. In the new subordinate, circuits for offensive behavior become less excitable and those for defensive behavior become more excitable. Serotonin, which is implicated in mechanisms for social dominance in many animals, modulates circuits for escape and avoidance responses in crayfish. The modulatory effects of serotonin on the escape circuits have been found to change with social dominance, becoming excitatory in dominant crayfish and inhibitory in subordinates. These changes in serotonin's effects on escape affect the synaptic response to sensory input of a single cell, the lateral giant (LG) command neuron for escape. Moreover, these changes occur over a 2-week period and for the subordinate are reversible at any time following a reversal of the animal's status. The results have suggested that a persistent change in social status leads to a gradual change in the expression of serotonin receptors to a pattern that is more appropriate for the new status. To test that hypothesis, the expression patterns of crayfish serotonin receptors must be compared in dominant and subordinate animals. Two of potentially five serotonin receptors in crayfish have been cloned, sequenced, and pharmacologically characterized. Measurements of receptor expression in the whole CNS of dominant and subordinate crayfish have produced inconclusive results, probably because each receptor is widespread in the nervous system and is likely to experience opposite expression changes in different areas of the CNS. Both receptors have recently been found in identified neurons that mediate escape responses, and so the next step will be to measure their expression in these identified cells in dominant and subordinate animals.
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Houpt, K. A., & Wolski, T. R. (1980). Stability of equine hierarchies and the prevention of dominance related aggression. Equine Vet J, 12(1), 15–18.
Abstract: The dominance hierarchy of a herd of 10 Thoroughbred mares was determined twice, at an interval of 18 months, using paired feeding tests. Each mare's rank was correlated significantly between the 2 tests. This indicated that the hierarchy within the herd was stable. The offspring of dominant and subordinate mares were also tested for dominance in their own age groups. The offspring of dominant mares tended to be near the top of the hierarchy while those of middle and low ranking mares were not consistently found in the middle or bottom of their own hierarchies. Paired feeding tests were carried out on 8 ponies. During tests the time that each pony spent eating and the ponies' aggressive interactions were recorded. Two situations were used. Each pony-pair was tested when both ponies were in the same paddock and also when they were separated by a rail fence. The subordinate ponies spent significantly more time eating and the domonant pony was significantly less aggressive, when the pony-pair was separated by a fence than when they were in one paddock. It was concluded that the dominance hierarchies of adult horse groups changed very little over time and that the foals of dominant mares will tend to be dominant in their own age groups. Management practices can be used to reduce aggression and consequent injury that may arise in group feeding situations.
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Collery, L. (1974). Observations of equine animals under farm and feral conditions. Equine Vet J, 6(4), 170–173.
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Noë, R., de Waal, F. B., & van Hooff, J. A. (1980). Types of dominance in a chimpanzee colony. Folia Primatol (Basel), 34(1-2), 90–110.
Abstract: This study examines to what extent the concept of dominance can be used to describe the social structure of a group of semi-free-living chimpanzees. 15 behavioural variables, based on agonistic, competitive and affinitive behaviour patterns, have been compared with respect to the interindividual directions in which they occurred. In this analysis use was made of indices that reflect the position an individual occupies in the relationship structure. These indices were calculated per individual for all variables and subjected to factor analysis and cluster analysis. As a result, 13 of the variables could be grouped in three categories which have been labelled: (1) agonistic dominance; (2) bluff dominance, and (3) competitive dominance. Whereas the top positions in the hierarchies based on the first two closely related types of dominance were occupied by the adult males, the hierarchy based on the third type was headed by several adult females.
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Saayman, G. S. (1971). Behaviour of the adult males in a troop of free-ranging Chacma baboons (Papio ursinus). Folia Primatol (Basel), 15(1), 36–57.
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Jolly, A. (1998). Pair-bonding, female aggression and the evolution of lemur societies. Folia Primatol (Basel), 69 Suppl 1, 1–13.
Abstract: Lemur societies have been described as convergent with those of anthropoids, including Papio-like female-bonded multi-male groups. Recent research, however, shows at least 5 pair-bonded species among the Lemuridae and Indriidae. Three more, Eulemur mongoz, Eulemur fulvus and Varecia variegata, have societies combining aspects of pairing with aspects of troop life. The best-known female-bonded societies, those of Lemur catta, Propithecus diadema edwardsi and Propithecus verreauxi, may be assemblages of mother-daughter dyads, capable of high aggression towards other females, but derived from more solitary female ancestors, perhaps also living as pairs. The internal structure of such lemur groups differs from the more extensive kin groups of catarrhines. This in turn may relate to the lemurs' level of social intelligence and to lemur female dominance over males.
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Rudran, R. (1973). Adult male replacement in one-male troops of purple-faced langurs (Presbytis senex senex) and its effect on population structure. Folia Primatol (Basel), 19(2), 166–192.
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Reimers, M., Schwarzenberger, F., & Preuschoft, S. (2007). Rehabilitation of research chimpanzees: stress and coping after long-term isolation. Horm Behav, 51(3), 428–435.
Abstract: We report on the permanent retirement of chimpanzees from biomedical research and on resocialization after long-term social isolation. Our aim was to investigate to what extent behavioral and endocrine measures of stress in deprived laboratory chimpanzees can be improved by a more species-typical social life style. Personality in terms of novelty responses, social dominance after resocialization and hormonal stress susceptibility were affected by the onset of maternal separation of infant chimpanzees and duration of deprivation. Chimpanzees, who were separated from their mothers at a younger age and kept in isolation for more years appeared to be more timid personalities, less socially active, less dominant and more susceptible to stress, as compared to chimpanzees with a less severe deprivation history. However, permanent retirement from biomedical research in combination with therapeutic resocialization maximizing chimpanzees' situation control resulted in reduced fecal cortisol metabolite levels. Our results indicate that chimpanzees can recover from severe social deprivation, and may experience resocialization as less stressful than solitary housing.
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Mitman, G. (1990). Dominance, leadership, and aggression: animal behavior studies during the Second World War. J Hist Behav Sci, 26(1), 3–16.
Abstract: During the decade surrounding the Second World War, an extensive literature on the biological and psychological basis of aggression surfaced in America, a literature that in general emphasized the significance of learning and environment in the origins of aggressive behavior. Focusing on the animal behavior research of Warder Clyde Allee and John Paul Scott, this paper examines the complex interplay among conceptual, institutional, and societal forces that created and shaped a discourse on the subjects of aggression, dominance, and leadership within the context of World War II. The distinctions made between sexual and social dominance during this period, distinctions accentuated by the threat of totalitarianism abroad, and the varying ways that interpretations of behavior could be negotiated attests to the multiplicity of interactions that influence the development of scientific research.
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Feist, J. D., & McCullough, D. R. (1975). Reproduction in feral horses. J Reprod Fertil Suppl, (23), 13–18.
Abstract: A behavioural study of feral horses was conducted on the Pryor Mountain Wild Horse Range in the western United States. All 270 horses on the Range were identified individually. The sex ratio was nearly balanced. Foal to adult female ratio was 43-2:100. Morality was concentrated among foals and old horses. Horses were organized as forty-four harem groups each with a dominant stallion, one to two immature stallions, one to three immature mares, one to three adult mares and their yearling and foal offspring, and 23 bachelor groups of one to eight stallions. Harem groups were quite stable year-round because of dominance and leadership by the stallions and group fidelity by mares and their offsring. Most changes occurred during the breeding season and involved immature females. Defeat of dominant stallions was infrequent. Immature males were tolerated because of their submissive behaviour. Bachelor stallion groups were inherently unstable. Mares came into heat after foaling in May/June, and were mated by harem stallions only.
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