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Kaseda Y,. (1981). The structure of the groups of Misaki horses in Toi Cape. Jpn. J Zootech Sci, 52, 227–235.
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Rubenstein Di,. (1981). Behavioural ecology of island feral horeses. Equine. Vet. J., 13, 27–34.
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SchäFer M,. (1981). Beobachtungen zum interspezifischen Aggressionsverhalten eines Halbeselhybrid. Säugetierk Mitt, 29, 49–58.
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Partridge, B. L. (1981). Internal dynamics and the interrelations of fish in schools. J Comp Physiol Sensory Neural Behav Physiol, 144(3), 313–325.
Abstract: The three-dimensional structure of schools of saithe (Pollachius virens) and the interactions between individuals over time were analyzed in 12,240 frames of videotape sampled at 2.7 Hz. Time series analyses of the interactions between identified individuals allowed testing of assumptions of anonymity vs. leadership in schools and investigation of the transfer of information between individuals by which collective decisions are made. Results include the following:1.Saithe match changes in both swimming direction and speed of their neighbors but correlations are greater for swimming speed. Average speed of the school does not greatly affect correlations between neighboring fish although the reaction latencies may be somewhat increased. As shown previously (Partridge et al. 1980) nearest neighbor distance (NND) decreases with increasing school velocity.2.Saithe simultaneously match the headings and swimming speeds of at least their first two nearest neighbors within the school (NN1 and NN2). Partialling out the correlation between a fish's neighbors demonstrates that a fish's correlation to his second nearest neighbor (NN2) is not simply a transitive function of mutual correlation between the NN1 and NN2.3.Several sources of individual variation in schooling performance were examined. In all respects except one, that of preferred positions within the school, saithe showed no individual differences, i.e., some were not “better schoolers” than others. Although fish in the school differed in length by up to a factor of 2.5, no size related effects in NND or nearest neighbor positioning were found.4.Single Linkage Cluster Analysis (SLCA) of the cross-correlations of fishs' swimming speeds and directions demonstrated quantitatively the existence of subgroups within schools if they contain more than 10-11 members. Subgroups acting more-or-less independently in terms of short term variations in speed and direction nonetheless remained within the school as a whole and were not often apparent to observers since members of one group interdigitated with those of another. How individuals know to which subgroup they belong remains unanswered.
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Cambefort, J. P. (1981). A comparative study of culturally transmitted patterns of feeding habits in the chacma baboon Papio ursinus and the vervet monkey Cercopithecus aethiops. Folia Primatol (Basel), 36(3-4), 243–263.
Abstract: Japanese workers have studied social acquisition patterns of new feeding habits in Macaca fuscata which they have termed precultural. The present study investigates the same phenomenon in the chacma baboon and the vervet monkey in their natural habitat. The questions addressed are: (1) How a new feeding habit enters a troop and by which age and sex category, also how it is propagated? (2) When individuals are permitted with a choice between palatable and unpalatable food, can they learn by demonstration only or do they have to pass through a direct learning process? (3) Can the results from the above questions be explained by social parameters such as the social structure of the individual species? It was found that juvenile baboons discover new food and that after the discovery propagation is instantaneous. In vervets discovery is random among the age classes and propagation is slow and takes place through certain 'pivot' individuals. Both species fail to learn about palatability by demonstration but have to go through a direct learning process. This contrasts strongly with the forest baboon Mandrillus sphinx that have been shown to learn by demonstration. Socially, baboon juveniles stay closer to each other than the adults who force them to live at the periphery of the troop. Vervets again forage without precise sub-group formation. The link between social and cultural propagation and social structure is discussed on the basis of these findings.
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Roberts, J., Hunter, M. L., & Kacelnik, A. (1981). The ground effect and acoustic communication. Anim. Behav., 29(2), 633–634.
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Miller, R. (1981). Male aggression, dominance and breeding behaviour in Red Desert feral horses. Z. Tierpsychol., 57, 340–201.
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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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Houpt, K. A. (1981). Equine behavior problems in relation to humane management. Int. J. Stud. Anim. Prob., 2(6), 329–337.
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