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Klimov, V. V. (1988). Spatial-ethological organization of the herd of Przewalski horses (Equus przewalskii) in Askania-Nova. Appl. Anim. Behav. Sci., 21(1-2), 99–115.
Abstract: The ethological structure of the herd of Przewalski horses includes hierarchic ranks of horses which determine their social roles in the herd. Besides the age ranks, the wild horses are characterized by the formation of harem groups, a “leading” group of females, a group of bachelor stallions, family groups, etc. The ethological structure determines the spatial one, which is the form of distribution of horses over the territory, and its assimilation and transformation into a system of informative spatial units. Under the influence of “internal” and “external” stimuli, the intragoup regulatory mechanims (social adaptations) manifest themselves, which allow the herd to function in the complicated situation of the reserve and allow humans to control the herd by using these mechanisms. There are grounds to believe that, given the balanced ethological structure of these groups, wild horses could be successfully acclimatized into natural biotopes.
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Kolter, L., & Zimmermann, W. (1988). Social behaviour of Przewalski horses (Equus p. przewalskii) in the Cologne Zoo and its consequences for management and housing. Appl. Anim. Behav. Sci., 21(1-2), 117–145.
Abstract: Between 1977 and 1986, two actual rank changes and two unsuccessful attempts occurred among the mares of the Cologne herd. The stallion was at first a low-ranking individual, but attained a dominant position during the last 3 years. At this time he started to split his group and thus to affect attachment relationships among his mares. During his absence of half a year, new bonds resulted and disappeared again some months after his return. Foals were tolerated by the sire for a long time. His behaviour to young, sub-adult mares varied with the individual. Protection of sub-adult mares by adult mares against the stallion's attacks may occur. Young mares protect and guard strange foals from their very first day. Management steps to cope with social and feeding problems consisted of enlargement and adding complexity to the enclosure, the establishment of more feeding sites, building a stable and temporary removal of the stallion.
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Ryder, O. A., & Massena, R. (1988). A case of male infanticide in Equus przewalskii. Appl. Anim. Behav. Sci., 21(1-2), 187–190.
Abstract: Following the introduction of a new stallion to a band of E. przewalskii mares two births, both of male foals, resulted in foal death due to injuries sustained in the first day of life. Neither foal was sired by the new herd stallion. The second foal death was the results of an observed attack on the newborn male and is described here. Subsequently births in the same enclosure and, in one instance, to the same mare whose previous foal was killed, were of foals sired by the new stallion and were uneventful, with 3 male foals surviving to date.
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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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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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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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Huff, A. N. (1988). Winter Manegement. Journal of Equine Veterinary Science, 8(1), 81.
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Huff, A. N. (1988). Safety. Journal of Equine Veterinary Science, 8(1), 81.
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Bednarz, J. C. (1988). Cooperative Hunting Harris' Hawks (Parabuteo unicinctus). Science, 239(4847), 1525–1527.
Abstract: Coordinated hunting by several individuals directed toward the capture and sharing of one Large prey animal has been documented convincingly only for a few mammalian carnivores. In New Mexico, Harris' hawks formed hunting parties of two to six individuals in the nonbreeding season. This behavior improved capture success and the average energy available per individual enabled hawks to dispatch prey larger than themselves. These patterns suggest that cooperation is important to understanding the evolution of complex social behavior in higher vertebrates and, specifically, that benefits derived from team hunting a key factor in the social living of Harris' hawks.
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McCann, J. S., Heird, J. C., Bell, R. W., & Lutherer, L. O. (1988). Normal and more highly reactive horses. II. The effect of handling and reserpine on the cardiac response to stimuli. Appl. Anim. Behav. Sci., 19(3-4), 215–226.
Abstract: A split-plot experiment evaluated the effect of handling and reserpine on the autonomic heart-rate response of yearling horses to various stimuli. The emotionality levels of 32 Quarter-Horse yearlings were rated by 4 experienced horsemen on a scale from 1 to 4 (1 = most nervous and erratic disposition; 4=quiet disposition). The yearlings were subsequently classified and penned based on their emotionality level; normal or nervous. Within each emotionality group, one-half the yearlings were handled daily for 14 days and the other one-half remained free in the pens. Following the handling treatment, every yearling was individually exposed to a series of stimuli, while the heart rate was monitored via a radio-telemetry system. A second treatment, reserpine, was subsequently given intramuscularly (0.005 mg/kg body weight) to one-half the yearlings of each treatment combination of emotionality and handling. The heart rate of the yearlings to the same series of stimuli previously employed was determined at 24 and 120 h and 16 days following the reserpine injection. Summarizing the results, the handled yearlings tended to exhibit lower heart rates with the handling stimulus, but the heart rate with a more novel stimulus was not affected by the previous handling treatment. Reserpine tended to suppress the heart rate of the unhandled group during the presence of a handler, but the permanency of this effect was not evident 16 days after the drug was administered. The reserpine-treated groups tended to exhibit the lowest heart-rate response to stimuli during the 120-h test-day following the administration of the drug. Heart-rate responses to the stimuli were not different between the normal and nervous yearlings.
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