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Harrington, F. H. (1987). Aggressive howling in wolves. Anim Behav, 35.
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Drevemo, S., Fredricson, I., Hjertén, G., & McMIKEN, D. (1987). Early development of gait asymmetries in trotting Standardbred colts. Equine. Vet. J., 19(3), 189–191.
Abstract: Summary Ten trotting Standardbred colts were recorded by high-speed cinematography at the ages of eight, 12 and 18 months. The horses were trotting on a treadmill operating at 4.0 m/secs. Five horses were subjected to a programme of intensified training from eight months of age, whereas the others were not trained and acted as controls. The films were analysed on a semi-automatic film-reading equipment and a number of variables used to demonstrate the gait symmetry were calculated and scaled by computer. Certain differences between left and right diagonal and contralateral pair of limbs, respectively, were noted, suggesting that laterality in horses may be inherited. The most pronounced systematic differences were found in 18-month old horses in the trained group. The results show the importance of careful gait examination and comprehensive coordination training at an early age.
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Kruska, D. (1988). Mammalian domestication and its effect on brain structure and behavior. In H. J. Jerison, & I. Jerison (Eds.), Intelligence and Evolutionary Biology. New York: Springer-Verlag.
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O'Brien, P. H. (1988). Feral goat social organization: a review and comparative analysis. Appl Anim Behav Sci, 21.
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Jerison H. J. (1988). Intelligence and Evolutionary Biology (J. J. Jerison H. J., Ed.).
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Fuller, T. K., & Sampson, B. A. (1988). Evaluation of a simulated howling survey for wolves. J Widl Manag, 52.
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Harrington, F. H. (1989). Chorus howling by wolves: Acoustic structures, pack size and Beau Geste effect. Bioacoustics, 2.
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Galef, B. G. (1989). Enduring social enhancement of rats' preferences for the palatable and the piquant. Appetite, 13(2), 81–92.
Abstract: In three experiments on the social induction of food preferences in rats, I found: (a) that eight 30-min exposures of a naive “observer” rat to a “demonstrator” rat fed one of two approximately equipalatable diets produced observer preference for the diet fed to its demonstrator that lasted for more than a month, (b) that simple exposure of naive subjects to a diet itself, rather than to a rat that had eaten a diet, was not sufficient to enhance preference for that diet, and (c) that lasting preference for an unpalatable, piquant diet could also be established by exposing naive rats to demonstrators that had eaten the piquant diet, but not by simply exposure to the piquant diet itself. These findings are consistent with the hypothesis proposed by both Birch and Rozin that social-affective contexts are important in establishing stable, learned preferences for foods.
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Smith, S. F., Appleby, M. C., & Hughes, B. O. (1990). Problem solving by domestic hens: opening doors to reach nest sites. Appl. Anim. Behav. Sci., 28(3), 287–292.
Abstract: In a trial of cage designs for laying hens, eggs were discovered in dust baths where access was restricted by a closed door during the normal laying period (08:00-13:00 h). Observations showed that the hens in these dust bath treatments had developed methods of opening the doors in order to lay in the baths. Three different methods of opening were observed. An average time of 34.4 min was spent attempting to open the doors before access was finally achieved. This implies a strong nesting motivation in these hens. The proportion of eggs laid in the dust baths increased (with occasional fluctuations) over a 24-week period. Door opening is likely to have initially developed in one individual in each cage through a trial and error basis, and then have been learned by cage mates through imitation. The speed and efficiency of door opening was not found to increase with experience or time.
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Petherick, J. C., & Rutter, S. M. (1990). Quantifying motivation using a computer-controlled push-door. Appl. Anim. Behav. Sci., 27(1), 159–167.
Abstract: A computer-controlled push-door system was designed and tested as a method for measuring motivation. Eleven domestic hens were trained to use the push-door to gain access to food. They were deprived of food for 12 h or 43 h on 12 occasions and the push-door was used to measure the amount of “work” (measured as force × time) that they performed to gain access to a food reward. When deprived of food for 12 h the hens took significantly longer (P<0.01) to reach the required threshold of work, than when deprived for 43 h. This difference arose from the amount of time that the hens spent not pushing at the door. The problems encountered with this system and such an approach to measuring motivation are discussed.
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