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Penzhorn, B. L., & Novellie, P. A. (1991). Some behavioural traits of Cape mountain zebras (Equus zebra zebra) and their implications for the management of a small conservation area. Appl. Anim. Behav. Sci., 29(1-4), 293–299.
Abstract: The social organisation of mountain zebras (Equus zebra zebra) consists of breeding herds (1 male, 2.4 females (range 1-5) and their offspring) which remain stable over many years, and bachelor groups. Foals leave their maternal herds of their own accord. In a free-ranging population the behaviour of the foals in leaving the herd is probably an adequate mechanism to prevent inbreeding, but inbreeding may occur in confined populations. Individual recognition by means of stripe pattern allows a check to be kept. Seasonal movement of mountain zebras is associated with a relative change in diet quality (as indicated by crude protein contents of preferred food plants and of faeces) between summer and winter habitats. Any conservation area should be large and varied enough to include both summer and winter habitats. Mountain zebras favour taller grass than most antelope species, harvesting their food at 50-150 mm from the ground. The existence of large populations of antelope could, therefore, be detrimental to zebras.
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Noë, R., van Schaik, C. P., & van Hooff, J. A. R. A. M. (1991). The Market Effect: an Explanation for Pay-off Asymmetries among Collaborating Animals. Ethology, 87(1-2), 97–118.
Abstract: Abstract * 1Animals can derive leverage over others from (a) resource holding power, based for instance on fighting ability or dominance, and (b) the possession of commodities, such as special skills and resources that cannot be taken away by force. * 2We contend that power based on the possession of commodities strongly depends on the level of supply and demand for that commodity, a phenomenon we call the ‘market effect’. * 3Several theoretical and empirical examples are given of social systems in which animals belong to two distinct classes that offer two different kinds of commodities. * 4The relative frequency of occurrence of the two classes is shown to determine the relative power of their members. * 5We consider the theoretical properties of bargaining processes by which relative power is converted into corresponding pay-off distributions. * 6We propose coalition games, a class of games with more than two players and in which bargaining is possible, as suitable paradigms for collaboration among members of social units.
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Potts, W. K., Manning, C. J., & Wakeland, E. K. (1991). Mating patterns in seminatural populations of mice influenced by MHC genotype. Nature, 352(6336), 619–621.
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Chase, M. W., & Hills, H. H. (1991). Silica Gel: An Ideal Material for Field Preservation of Leaf Samples for DNA Studies. Taxon, 40(2), 215–220.
Abstract: Silica gels an inexpensive and reliable substance to preserve field-collected leaves for molecular studies of variation in DNA. A method for its utilization is explained, and results are presented, comparing total cellular DNA samples extracted from a set of fresh and silica-gel dried samples of the same species, as well as examining the efficiency of endonuclease restriction and intactness of DNA from of a set of field-collected leaves preserved with silica gel.
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Sato, S., Sako, S., & Maeda, A. (1991). Social licking patterns in cattle (<em>Bos taurus</em>): influence of environmental and social factors. Applied Animal Behaviour Science, 32(1), 3–12.
Abstract: To investigate the functions of social licking in cattle, four calves (one heifer and one steer in each of two herds), known to exhibit frequent social licking were observed continuously for 2 h before sunset for 13 days, using the focal animal sampling method. Calves were observed under various environmental conditions. Social licking significantly decreased on rainy days and tended to increase in a dirty barn and when food was restricted. Solicitation for social licking occurred not only from dominant animals of pairs but also from subordinates. Of the licking interactions, 31% occurred following solicitation, and these accounted for 39% of the total time spent licking. Following solicitation, 78% of social licking was oriented to the head and the neck regions that were inaccessible to self-licking animals. Unsolicited licking, however, was oriented not only to the head and the neck but also to the back and the rump regions, and these two latter regions were the major ones to receive licking. The effect of social relationships on social licking was investigated using least-squares analysis of variance. Social factors investigated were the difference of dominance values, the dominance-subordinance relationship, and kinship and familiarity; the sex of calves involved was also considered. Only familiarity had a significant effect on licking; exchanges of social licking increased with length of cohabitation. We suggest that social licking may have a cleaning effect, a tension-reducing effect and a bonding effect.
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Lee, P. (1991). Adaptation to environmental change:an evolutionary perspective. In H. O. Box (Ed.), Primate responses to environmental changes (pp. 39–56). London: Chapmann & Hall.
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