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Hildebrand, M. (1987). The Mechanics of Horse Legs. Amer. Sci., 75(6), 594–601.
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Harrington, F. H. (1987). Aggressive howling in wolves. Anim Behav, 35.
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Kacelnik, A. (1987). Information primacy or preference for familiar foraging techniques? A critique of Inglis & Ferguson. Anim. Behav., 35(3), 925–926.
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Giraldeau, L. - A., & Lefebvre, L. (1987). Scrounging prevents cultural transmission of food-finding behaviour in pigeons. Anim. Behav., 35(2), 387–394.
Abstract: Living in groups should promote the cultural transmission of a novel behaviour because opportunities for observing knowledgeable individuals are likely to be more numerous in this condition. However, in this study pigeons who shared the food discoveries of others (scroungers) did not learn the food-finding technique used by the discoverers (producers). Individually-caged pigeons prevented from scrounging easily learned the technique from a conspecific tutor. When caged pigeons obtained food from the tutor's performance, most naïve observers failed to learn. In a flock, scroungers selectively followed producers. In individual cages, scrounging during the tutor's demonstration was equivalent to getting no demonstration at all. This effect of scrounging did not interfere with subsequent acquisition of the food-finding behaviour when scrounging was no longer possible.
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Sherwin, C. M., & Johnson, K. G. (1987). The influence of social factors on the use of shade by sheep. Appl. Anim. Behav. Sci., 18(2), 143–155.
Abstract: Individual differences in shading behaviour within a flock of sheep could be due to differences in thermoregulatory capabilities or to the influence of social factors. The possible influence of social factors on shade-use is examined in this paper. Two measures of dominance were made on 39 Merino wethers. These were based on the hierarchy determined by butting during feeding and on priority of access to limited feed. Leadership was also assessed while driving the sheep to a woolshed and as the sheep entered weighing scales. These behavioural traits were compared with leadership to shade and shade-use observed on 9 days during summer in a small pastureless enclosure containing natural shade. Maximum ambient temperature on these 9 days varied between 29.0 and 39.5[degree sign]C. All behavioural traits examined were significantly repeatable. The two dominance ranks were negatively correlated (P<0.05). The butting hierarchy was correlated with shading behaviour; those sheep that butted the larger proportion of the flock were seen to shade for longer periods of time (P=0.05). This relationship became more significant as environmental temperature increased. Significant (P<0.05) differences in the amount of time each sheep spent shading were evident throughout the flock, but in particular seven individuals shaded much less than others. Shade-use increased in hot weather and was slightly more strongly correlated with radiation load than with air temperature. The non-shading leadership ranks were related neither to each other nor to the leadership to shade. However, the sheep that moved to shade first remained there longest (P<0.05). Reduced motivation to feed did not appear to explain early movement to shade. Few overtly aggressive or other interactions between animals were seen to be associated with movements to or within shade. Nonetheless, the results indicate that social forces do exert some influence on shade-use.
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Crowell-Davis, S. L., Houpt, K. A., & Kane, L. (1987). Play development in Welsh pony (Equus caballus) foals. Appl. Anim. Behav. Sci., 18(2), 119–131.
Abstract: The structure of the play of colts and fillies living on pasture was studied from birth (n = 15) for up to 24 weeks. Foal play was categorized as running and bucking alone, running and bucking in a group, interactive (contact or combat) play, play with an object, and play at an adult. The rate of play decreased with increasing age and ambient temperature. Fillies and colts played with equal frequency, but engaged in some different types of play at different rates. There was no difference between colts and fillies in the proportion of play bouts of running and bucking in a group or playing with an object. Fillies engaged in running and bucking alone more than colts. Colts engaged in interactive play and play at an adult more than fillies. While there was no significant difference between colts and fillies in the duration of either type of running and bucking play, the interactive play bouts of colts were significantly longer than those of fillies. Both mares and stallions were tolerant of foal play which involved use of their body as a play object, including mounting play. Both fillies and colts engaged in mounting play. Foals used various natural objects found in the pasture for repeated bouts of play with inanimate objects, a behaviour which may explain, from a developmental perspective, the occasional use of “tools” in adult equids. The sex differences in type of play were consistent with the social structure of unmanaged adults in which males must compete with each other in order to associate with females.
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Crowell-Davis, S. L. (1987). Self-grooming by mares and foals of the Welsh pony (Equus caballus). Appl. Anim. Behav. Sci., 17(3-4), 197–208.
Abstract: Self-grooming behaviour of 15 mare-foal pairs was studied weekly for the first 24 weeks of the foal's life. Mares self-groomed at mean rates of 1.2-2.2 times h-1 depending on the 4-week period. Foals self-groomed more often, with a peak rate of 12.3 times h-1 occurring during Week 5-8 and a subsequent decline to 6.0 times h-1 by Weeks 21-24. Self-grooming bouts of mares and foals also differed in the proportion devoted to each type of self-grooming. During a greater proportion of their total self-grooming bouts, foals scratched their head and neck with a hind limb or bit and scratched the trunk or hind limbs with the teeth. The mares spent a greater proportion of their self-grooming bouts rubbing their head or neck on an inanimate object, another pony, or their fore limb, or rolling on the ground. Particular types of individual self-grooming bouts were engaged in for different lengths of time. Foals had longer bouts of scratching the head and neck with a hind limb, scratching or biting the fore limb or hind limb with the teeth, and rubbing the head and neck on an inanimate object, while mares had longer bouts of rolling. Some of the differences in preference for particular types of self-grooming may be the result of differences in relative size of various body parts and, consequently, relative ease of a given type of self-grooming.
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Rapaport, L., & King, N. E. (1987). The behavioral research program at the Washington Park Zoo. Appl. Anim. Behav. Sci., 18(1), 57–66.
Abstract: For the past decade, the Washington Park Zoo, Portland, Oregon, has had an active behavioral research program. The research department is both a zoo-supported research facility for visiting researchers and staff, and an educational facility that teaches practical behavioral research methods to undergraduates. The research education program utilizes students from any of a dozen local colleges and universities. Students receive academic credit for their participation. Active keeper-participation plays a major role in many research projects. Not only does keeper-cooperation facilitate research, but their knowledge of the individual animals often proves invaluable. In addition to involvement in student projects, keepers have also conducted their own research projects.
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Lisa Nash, H., Song, G. K., & Price, E. O. (1987). Head partitions facilitate feeding by subordinate horses in the presence of dominant pen-mates. Appl. Anim. Behav. Sci., 19(1-2), 179–182.
Abstract: The purpose of the following study was to determine if head partitions would facilitate feeding by subordinate horses in the presence of dominant pen-mates. Six pairs of mares, each with established dominant-subordinate relationships, were allowed to compete for feed in a 112-cm trough following 24 h of deprivation. Time spent feeding by each mare in each pair was recorded with a wire-mesh partition, a solid plywood partition or no partition dividing the trough. Differences in feeding times between dominant and subordinate mares were greatest in the absence of a partition and least (P<0.05) with the wire barrier in place. Differences in feeding times with the solid plywood barrier were not significantly different from either of the other treatment conditions. It was concluded that head partitions on a trough facilitate feeding by subordinate horses in the presence of dominant pen-mates and thus provide a more equitable distribution of food resources.
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Hunte, W., & Horrocks, J. A. (1987). Kin and non-kin interventions in the aggressive disputes of vervet monkeys. Behav. Ecol. Sociobiol., 20, 257–263.
Abstract: Interventions in aggressive disputes were investigated in a free-living troop of vervets (Cercopithecus aethiops sabaeus) in Barbados. Interventions on behalf of kin were more frequent than on behalf of non-kin. Both types of interventions were more likely when the intervening animal outranked the opponent; presumably because retaliation probability, and hence cost of intervening, is low against low ranking opponents. The number of interventions given on behalf of both kin and non-kin increased with the number of disputes in which they were involved. In contrast to kin interventions, the number of interventions given on behalf of non-kin was correlated with that received by non-kin, suggesting that reciprocation is a necessary component of non-kin interventions. Non-kin interventions were more likely when the recipient outranked the opponent, presumably because reciprocation probability is high. Pairs of non-kin form structured reciprocal relationships based on the proportion of interventions allocated to each other, and most non-kin interventions flowed through these relationships. Males intervened on behalf of non-kin more frequently than did females. The implications of the results for the evolution of kin and reciprocal altruism were discussed.
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