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Thackeray, J. F. (1988). Zebras from wonderwerk cave, northern Cape province, South Africa: attempts to distinguish Equus burchelli and E. quagga. Suid- Afrikaanse Tydsskrif vir Wetenskap, 84, 99–101.
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Westlin-van Aarde, L. M., van Aarde, R. J., & Skinner, J. D. (1988). Reproduction in female Hartmann's zebra. J Reprod Fert, 84, 505–511.
Abstract: Ovaries, fetuses and plasma were collected from zebra mares shot in the Etosha National Park in Namibia between 15 and 25 August 1983. Ovarian weight was affected by reproductive status and most of the non-pregnant mares were anoestrous. The number of follicles varied between individuals and only pro-oestrous/oestrous mares had follicles larger than 20 mm in diameter. The largest follicle in pregnant mares was only 9 mm in diameter. Corpora lutea and corpora albicantia were found in non-pregnant as well as pregnant mares: 4 pregnant mares had only corpora albicantia. The presence of secondary corpora lutea could not be confirmed in any of the pregnant mares. Implantation was estimated to occur at around 73 days of gestation, and most mares (84%) had conceived between November and April. Peripheral concentrations of plasma progesterone during pregnancy varied from 0·5 to 2·4 ng/ml.
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Boyd, L. E., Carbonaro, D. A., & Houpt, K. A. (1988). The 24-hour time budget of Przewalski horses. Appl. Anim. Behav. Sci., 21(1-2), 5–17.
Abstract: A herd of 8 Przewalski horses were observed on pasture in summer. Fifteen-minute focal animal samples were used to determine the time budget of the horses during the periods 00.00-04.00, 04.00-08.00, 08.00-12.00, 12.00-16.00, 16.00-20.00 and 20.00-24.00 h EDT. The behavioral states recorded were feeding (grazing and eating grain), nursing, drinking, standing, stand-resting, self-grooming, mutual grooming, locomoting, playing, and lying laterally and sternally. The average number of behavioral states occurring per hour, and the defecation, urination, aggression and vocalization rates were also determined. Overall, the horses spent 46.4 +/- 5.9% of their time feeding, 1.3 +/- 0.1% nursing, 0.5 +/- 0.1% drinking, 20.6 +/- 5.4% standing, 15.7 +/- 3.2% stand-resting, 1.7 +/- 0.2% self-grooming, 2.2 +/- 0.7% mutual grooming, 7.4 +/- 1.0% locomoting, 1.2 +/- 0.3% playing, 1.2 +/- 0.5% lying laterally and 4.1 +/- 3.0% lying sternally. The horses averaged 45.2 +/- 5.8 behavioral states per hour, and 0.2 +/- 0.0 defecations, 0.3 +/- 0.0 urinations, 1.5 +/- 0.3 aggressions and 0.7 +/- 0.1 vocalizations per hour. The horses spent the greatest amount of time foraging between 20.00 and 04.00 h, when the temperatures were lower. They spent 68.2 +/- 2.2% of their time between 20.00 and 24.00 h feeding, but only 31.2 +/- 2.1% of their time feeding between 08.00 and 12.00 h. Recumbent rest was most common between 00.00 and 04.00 h. As temperatures rose during the daylight hours, the horses spent more time drinking and standing, rather than grazing. Stand-resting was the most common form of rest during the day. The horses exhibited the greatest number of activities per hour from 08.00 to 20.00 h. While standing in close proximity to one another during these hours, the horses exhibited the highest number of aggressions per hour (1.9-2.4).
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Carroll, C. L., & Huntington, P. J. (1988). Body condition scoring and weight estimation of horses. Equine Vet J, 20(1), 41–45.
Abstract: Three hundred and seventy two horses of varying breeds, height and fatness were weighed and measured for height at the withers. They were assessed for condition score by adaptation of a previously published method. The heart girth and length of 281 of the horses were also measured. Weight of horses was highly correlated (P less than 0.001) with height (r2 = 0.62), condition score (r2 = 0.22) and girth2 x length (r2 = 0.90). Nomograms were constructed to predict weight from height and condition score, and girth and length measurements. Weight can also be accurately estimated from the formula: (formula, see text) The average value of 'Y' in this experiment was 11900 and this estimated weight with more accuracy than some previously published values of 'Y'. Racing Thoroughbred horses were found to be significantly lighter than non-racing Thoroughbreds of the same height and condition score. The method of assessment of condition score was shown to be repeatable between different operators with varying degrees of experience.
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Boyd, L. E. (1988). Ontogeny of behavior in Przewalski horses. Appl. Anim. Behav. Sci., 21(1-2), 41–69.
Abstract: Twelve colts and 12 fillies were observed during their first 2 years of life. Data on the foal's nearest neighbor, distance to dam and stallion, and time budget were compiled by age. The birth of one foal was witnessed. During their first month of life, Przewalski foals were dependent on the dam. She provided most of their nourishment and foals spent 54% of their time within 1 m of her. The biggest change in behavior of foals occurred between Months 1 and 2. The amount of time spent resting and nursing declined, while the amount of time spent foraging increased sharply. Foals began to leave their mothers and interact with peers by 3 weeks of age, and at 2 months they were interacting with older herd members. By 5 months of age, the amount of time spent in most behaviors was identical to that of adults, except that vocalization rates and involvement in aggression were lower than for adults. Juveniles spent less time stand-resting than adults throughout their first year, but more time in recumbent rest. Foals spent far less time with their sire than with their dam. However, an orphaned foal spent more time with his sire than did mothered foals, indicating that the sire assumed part of the role of the missing dam.
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Levin, L. E., & Grillet, M. E. (1988). [Diversified leadership: a social solution of problems in schools of fish]. Acta Cient Venez, 39(2), 175–180.
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Berger, J., & Cunningham, C. (1988). Size-Related Effects on Search Times in North American Grassland Female Ungulates. Ecology, 69(1), 177–183.
Abstract: Feeding and searching (= vigilance) rates arise as a result of many interrelated factors including trophic level, diet, reproductive condition, sex, habitat, body mass, and potential predation pressure. Because of unique ecological conditions in which the confounding influences of all but two of these variables could be minimized, we examined the hypothesis that body mass alone accounts for interspecific differences in search times, and tested it with females of four sympatric native North American ungulates (Bison bison, Antilocapra americana, Ovis canadensis, and Odocoileus hemionus). When the effects of group size were controlled, smaller bodied species were more vigilant (per unit body mass) than larger ones. However, search times (ST) also scaled to body mass, and between 81 and 97% of the ST variance was explained by either exponential or power functions. To remove the potential bias that predators exert different influences on species of varying size, search times of bison in areas with and without their major predator, wolves (Canis lupus), were contrasted; search times did not differ between sites. Our results highlight the importance of designing field research that controls for confounding variables prior to attempting to scale behavioral processes to ecological events. See full-text article at JSTOR
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Berger, J.,. (1988). Social systems, resources, and phylogenetic inertia: an experimental test and its limitations. In C. N. Slobochikoff (Ed.), Ecology of Social Behavior (pp. 157–186). San Diego: Academic Press.
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Holzapfel, W. H., & Botha, S. J. (1988). Physiology of Sporolactobacillus strains isolated from different habitats and the indication of in vitro antagonism against Bacillus species. Int J Food Microbiol, 7(2), 161–168.
Abstract: In an ecological study only low numbers of Sporolactobacillus were found in habitats such as the faeces of herbivores, the rumen of cattle and the final waste water of an abattoir. Their presence in the final waste water of an abattoir indicates their possible association with food, and, more specifically, with meat. Differences were found in some physiological characteristics. One isolate (L2404) differed from the authentic Sporolactobacillus ATCC 15538 by its inability to ferment inulin, its growth in presence of 6.5% NaCl and in 0.2% tellurite, by the isomer(s) of lactic acid produced and the mol% G + G in the DNA. One Sporolactobacillus isolate (L2407) showed antagonism against Bacillus cereus, Bacillus cereus var, mycoides, Bacillus megaterium and Bacillus subtilis.
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Kozarovitskii, L. B. (1988). [Further comment on the distinction between humans and animals]. Nauchnye Doki Vyss Shkoly Biol Nauki, (3), 42–45.
Abstract: The problem of mind is considered in the aspect of natural scientific and philosophical problem of distinction between human and animal. The widespread confusion of the terms “rudiments”, “elements” of specifically human properties in animals and “biological prerequisites” of these properties are critically analysed. The idea is formulated according to which only in the process of anthropogenesis the rudiments of new social property--mind, conscience--could appear in the developing human beings.
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