Ginsberg, J. R.,. (1989). The ecology of female behaviour and male mating success in the Grevy's zebra. Symp zool Soc Lond, 61, 89–110.
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Klingel, H. (1989). Odd-toed Ungulates, Horses. In B. Grzimek (Ed.), Grzimek's Encyclopedia of Mammals (Vol. 4, 550+pp. 557–594). McGraw Hill.
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Rau, R. E.,. (1989). The museum's Quagga project.
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Rubenstein, D. I. (1989). Life history and social organization in arid adapted ungulates. J. Arid. Environ., 17, 145–156.
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de Waal, F. B. (1989). Dominance “style” and primate social organization. In V. Standen, & R. A. Foley (Eds.), Comparative Socioecology (pp. 243–263). Blackwell Science.
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Gallistel, C. R. (1989). Animal Cognition: The Representation of Space, Time and Number. Annual Review of Psychology, 40(1), 155–189.
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Cheney, D. L., & Seyfarth, R. M. (1989). Reconciliation and redirected aggression in vervet monkeys, Behaviour. Behaviour, 110, 258–275.
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Visalberghi E, & Trinca L. (1989). Tool use in capuchin monkeys: distinguishing between performing and understanding. Primates, 30, 511.
Abstract: A horizontal plexiglas tube containing a food-reward was presented to four naive tufted capuchins and suitable sticks were provided to push the reward out. Three monkeys out of four spontaneously used the tools and showed very different styles of solving the task. In more complex conditions, in which the sticks needed to be combined or actively modified in order to become effective, the monkeys were always successful; however, their performance was loaded with errors which did not disappear throughout the trials. Evidence of a difference between success in solving the problem and its understanding was found. This suggests that although capuchins can discover new means through active experimentation, they do not mentally represent the characteristics necessary for a tool to be effective, nor do they modify the tool appropriately beforehand. At this level, a major difference with chimpanzees emerges.
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McHugh, C. P. (1989). Ecology of a semi-isolated population of adult Anopheles freeborni: abundance, trophic status, parity, survivorship, gonotrophic cycle length, and host selection. Am J Trop Med Hyg, 41(2), 169–176.
Abstract: A population of adult Anopheles freeborni near Sheridan, CA was sampled daily during 13 August-7 September 1984. Data on abundance, trophic status, and gonotrophic age were recorded. Abundance and gonotrophic age data were analyzed to estimate daily survivorship and gonotrophic cycle length. Daily survivorship for unfed mosquitoes was estimated to be 0.72 with a gonotrophic cycle of 6 days duration. Daily survivorship for bloodfed mosquitoes was estimated to be 0.74 with a gonotrophic cycle of 4 days. The 2 day difference in gonotrophic cycles between unfed and bloodfed mosquitoes was the result of the period required for maturation and mating of teneral females. In 1986, an incage release of field-collected females estimated survivorship at 0.75 per day. Precipitin tests of 1,338 blood-engorged mosquito abdomens indicated that bovids, horses, rabbits, and canids comprised 92% of bloodmeals; no bloodmeals of human origin were detected.
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Trim, C. M., Moore, J. N., & Clark, E. S. (1989). Renal effects of dopamine infusion in conscious horses. Equine Vet J Suppl, (7), 124–128.
Abstract: An ultrasonic flow probe was implanted around a branch of the left renal artery in five horses. The effects of dopamine were studied in the unsedated horses 10 days after surgery. Three experiments, separated by at least two days, were performed in random order on each horse. In two experiments, dopamine was infused intravenously for 60 mins at either 2.5 and 5.0 micrograms/kg bodyweight (bwt)/min. Saline was infused for 60 mins before and after each infusion, and for 180 mins in the third experiment as a control. Renal blood flow increased during administration of dopamine at both dose rates (P = 0.0001). Urine volume increased (P = 0.055), and osmolality decreased (P < 0.05), with infusion of dopamine at 5.0 micrograms/kg bwt/min. Arterial blood pressure and heart rate were not significantly affected. Fractional excretions of sodium and potassium were not significantly changed with dopamine infusion. The higher dopamine dose rate was accompanied by dysrhythmias in some horses.
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