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Gingerich Pd,. (1981). Variation, sexual dimorphism, and social structure in the early Eocene horse Hyracotherium. Paleobiol, , 443–455.
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Gillan DJ, Premack D, & Woodruff G. (1981). Reasoning in the chimpanzee: I. Analogical reasoning. J. Exp. Psychol.: Anim. Behav. Process., 7, 1.
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COUGOUILLE-GAUFFRETEAU B et al,. (1981). Research on the consequences of the injection of male hormones... Comptes red Seanc Acad Sci, 292, 1073–1076.
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Clutton-Brock, J. (1981). Domesticated animals from early times. Austin: Univ of Texas Press.
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CLAYTON HM et al,. (1981). Some studies of comparative aspects of sexual behaviour in ponies and donkeys. App Anim Ethol, 7, 169–174.
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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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Bruns, E. (1981). Estimation of the breeding value of stallions from the tournament performance of their offspring. Livestock Production Science, 8(5), 465–473.
Abstract: Data from horse-riding competitions recorded in Germany in 1976 and 1977 have been analysed to estimate genetic parameters for performance traits of riding horses measured in dressage, jumping competitions and trials. The performance traits analysed were logarithmic earnings per start, relative place number, and place value. The results are the following. 1. (1) Heritability and repeatability estimates for performance in dressage shows are 0.2 and 0.4 respectively. Corresponding estimates for performance in jumping competitions are 20% less. No genetic differences are found between stallions for performance in trials.2. (2) A selection index for estimating the breeding value of stallions was constructed by using the repeated performances of their offspring in dressage and jumping shows. For this purpose, performance data for at least ten progeny should be available. The correlation between the breeding values estimated from the dressage and jumping performances of the same stallions was approximately zero.3. (3) Reliable progeny-testing requires that the assumptions of mating stallions at random, selecting progeny randomly, and distributing them equally across environmental effects be fulfilled.4. (4) The genetic use of breeding values of stallions estimated from the performance of their progeny is opposed by the prolongation of the generation interval. This can be partly overcome by sampling young stallions and making use of the test results for young progeny only.
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Boice, R. (1981). Behavioral comparability of wild and domesticated rats. Behav Genet, 11(5), 545–553.
Abstract: The oft-repeated concern for the lack of behavioral comparability of domestic rats with wild forms of Rattus norvegicus is unfounded. Laboratory rats appear to show the potential for all wild-type behaviors, including the most dramatic social postures. Moreover, domestics are capable of assuming a feral existence without difficulty, one where they readily behave in a fashion indistinguishable from wild rats. The one behavioral difference that is clearly established concerns performance in laboratory learning paradigms. The superiority of domestics in these laboratory tasks speaks more to quieting the concerns of degeneracy theorists than to problems of using domestic Norway rats as subjects representative of their species.
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Bernstein, I. S., & Dobrofsky, M. (1981). Compensatory social responses of older pigtailed monkeys to maternal separation. Dev Psychobiol, 14(2), 163–168.
Abstract: Thirteen 3-5-year-old pigtailed monkeys were subjected to five 2-hr maternal separations while remaining in their normal social group. Significant changes in activity profiles were noted during separation and reunion phases. This suggests the continued social dependence of older offspring upon the matriarch. The shift in social activities reflected attempts by the juvenile and adolescent subjects to compensate for maternal absence by intensification of other affiliative social behavior and avoidance of potentially socially disruptive situation. The subjects oriented more towards kin in the absence of the matriarch, but actual time with kin decreased. Upon the return of the matriarch, the intensified some responses depressed during her absence and returned to preseparation social relationships. Play and aggressive responses declined whereas social approaches increased during maternal absences. Submissive responses declined upon the return of the matriarch, and play increased. The subjects also showed a marked, temporary increase of direct interaction, largely sniffing and grooming, with the matriarch upon her return.
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Berger J,. (1981). The role of risks in mammalian combat: Zebra and onager fights. Z Tierpsychol 56, , 297–304.
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