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Heird, J. C., Lennon, A. M., & Bell, R. W. (1981). Effects of early experience on the learning ability of yearling horses. J. Anim Sci., 53(5), 1204–1209.
Abstract: Twenty-four yearling Quarter Horse fillies were divided into three groups (I) very limited handling, (II) intermediate handling and (III) extensive handling. At about 14 months of age, each horse was preconditioned for 2 weeks and then run in a simple place-learning T-maze test in which it had to locate its feed. Thirty trials were run daily for 20 days, with the location of the feed changed each day. To retire from the maze, a horse had to meet the criterion: 11 correct responses in 12 tries, with the last eight being consecutive. Horses in Group II required the fewest trials to reach criterion. These horses also learned more and had the highest percentage of correct responses (P less than .05). Mean trainability tended to predict learning ability; however, trainability and trials to criterion were not significantly correlated. Mean emotionality scores indicated a tendency for horses in the intermediately handled group to be less emotional than those in Group I or III. Results indicated that horses with an intermediate amount of handling scored higher on an intermediate test of learning. All handled horses scored higher on learning tests than those not handled.
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Barnard, C. J., & Sibly, R. M. (1981). Producers and scroungers: A general model and its application to captive flocks of house sparrows. Anim. Behav., 29(2), 543–550.
Abstract: Many forms of interaction within and between species appear to be based on `scrounger' individuals or species exploiting a limited resource provided `producers'. A mathematical model is presented which shows whether or not scroungers are maintained in a group, depending on their frequency and the group size. Some of the predictions of the model were tested in captive flocks of house sparrows Passer domesticus L. Here the scroungers obtained most of their food (mealworms) by interaction and the producers found most of their food by actively foraging: the pay-off to each type was measured as mealworm capture rate. Neither type changed strategy opportunistically in response to instantaneous flock composition but, not surprisingly, scroungers fared better when one of more producers were present. However, scrougers did much worse than expected when greatly outnumbered by producers, perhaps because producers then found the available food very quickly.
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McCall, C. A., Potter, G. D., Friend, T. H., & Ingram, R. S. (1981). Learning abilities in yearling horses using the Hebb-Williams closed field maze. J. Anim. Sci., 53(4), 928–933.
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Churcher, C. S. (1982). Oldest Ass Recovered from Olduvai Gorge, Tanzania, and the Origin of Asses. J. Paleontol., 56(5), 1124–1132.
Abstract: Abstract
An isolated right metatarsal III from an adult small monodactyl equid was recovered in situ from the middle of Bed II at Evelyn Fuchs-Hans Reck Korongo, Olduvai Gorge, Tanzania in 1963. Interosseous contacts for splint metatarsals II and IV are less evident than in any modern comparative Equus metapodials in Leiden, Holland, London, England or in the field in Africa: horses (E. caballus), zebras (E. burchellii, E. grevyi, E. quagga) and asses (E. a. asinus, E. a. africanus), of which the horses and asses were domesticates. The specimen is provisionally assigned to Equus (Asinus) asinus. The estimated height at the shoulders is less than a meter for the animal in life, comparable to a small donkey.
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Campitelli, S., Carenzi, C., & Verga, M. (1982). Factors which influence parturition in the mare and development of the foal. Appl. Animal. Ethol., 9(1), 7–14.
Abstract: Observations are reported of 127 foals born to 127 mares. In particular, comparisons are made between the mare's tendency to foal at night, the length of gestation, the weight of the foal and the weight of the foetal membrane, the time taken by the foal to attain a standing position and the time taken by the mare to expel the foetal membrane and the age of the mare and the season.
The new facts that emerge from the results are: (a) foals from middle-aged (6–11 years) mares are heavier; (b) variations of gestation length are related to the month of conception (just a trend, not a statistically significant result); (c) time for the foal to stand is related to the foal sex (females: 56.3 minutes; males 70.6 minutes, on average), and to the time taken by the mare to expel the foetal membrane; (d) parturitions take place mainly (80%) during the hours of darkness. In spring, the percentage of night births (85%) is higher than in winter (78%).
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Rescorla, R. A., & Holland, P. C. (1982). Behavioral Studies of Associative Learning in Animals. Annual Review of Psychology, 33(1), 265–308.
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Zahn-Waxler, C. & R. - Y., M. (1982). The development of altruism: Alternative research strategies. In N. Eisenberg (Ed.), The development of prosocial behavior (pp. 109–138). New York: Academic Press.
Abstract: Zahn-Waxler, C. & Radke-Yarrow, M. (1982) The development of altruism:
Alternative research strategies. In: The development of prosocial behavior, ed.
N. Eisenberg. Academic Press. [aSDP]
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Ristau, C. A. (1983). Language, cognition, and awareness in animals? Ann. N.Y. Acad. Sci., 406(1), 170–186.
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Appleby, M. C. (1983). The probability of linearity in hierarchies. Anim. Behav., 31(2), 600–608.
Abstract: The common practice of ranking a group of animals in the closest possible order to a linear dominance hierarchy assumes that dominance among those animals is generally transitive. In fact, analysis of groups in which dominance relationships are random shows that this method has a surprisingly high probability of producing an apparently linear or near-linear hierarchy by chance. As such, the existence of transitive dominance should be tested before it is used in ranking. A suitable statistical test is described here. Chance may also contribute to the linear appearance of hierarchies based on other factors.
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Moss, C. J., & Poole, J. H. (1983). Relationships and social structure in African elephants. In R. A. Hinde (Ed.), Primate social relationships: an integrated approach.. Blackwell Science Ltd.
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