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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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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Kirkpatrick, J. F., Kasman, L. H., Lasley,, B. L., & Turner, J. W. J. (1988). Pregnancy Determination in Uncaptured Feral Horses. J Wildl Manag, 52(2), 305–308.
Abstract: The urinary excretion of estrone sulfate ($\text{E}{1}\text{S}$) by 25 free-roaming feral horses (Equus caballus) was measured by radioimmunoassay applied to extracts of urine-soaked soil. Twelve of 15 mares having $\text{E}{1}\text{S}$ concentrations >1.0 mg/mg creatinine (x = 2.64 +- 1.02 [SD]) produced foals. All 10 mares with $\text{E}{1}\text{S}$ concentrations <1.0 mg/mg creatinine (x = 0.44 +- 0.26) did not foal. Extracting urine from soil and measuring $\text{E}{1}\text{S}$ and creatinine can be used to determine pregnancy in free-roaming feral horses without the stress of capture or immobilization.
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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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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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Black, J. M. (1988). Preflight Signalling in Swans: A Mechanism for Group Cohesion and Flock Formation. Ethology, 79(2), 143–157.
Abstract: Abstract The preflight behaviour of whooper swans Cygnus cygnus and Bewick's swans Cygnus columbianus bewickii was examined to determine the adaptive significance of the ritual. Analysis of the preflight sequence revealed that the rate of signalling became significantly faster as the time of takeoff approached. This provides the first quantitative evidence that a threshold of excitability is responsible for triggering synchronised flight in social units. Two ultimate and two proximate factors that affect this threshold were uncovered. They are: 1) Maintaining proximity to partners—flight was delayed by birds with non-attentive mates and signalling lasted on average four times longer than those whose mates showed more interest. 2) Maintaining flock cohesiveness—birds which performed signals for longer periods while swimming among uninterested birds were successful in attracting followers 61% of the time. 3) The bird's feeding performance related to dominance status—less successful feeders (potentially hungry birds), flew after little time and few signals. 4) The type of feeding opportunity at the eventual destination—birds which flew to provided feeds (nutritious barley) spent less time performing preflight signals than when they flew to forage on grass fields.
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de Waal, F. B. M., & Luttrell, L. M. (1988). Mechanisms of social reciprocity in three primate species: Symmetrical relationship characteristics or cognition? Ethology and Sociobiology, 9(2–4), 101–118.
Abstract: Agonistic intervention behavior was observed in captive groups of chimpanzees (Pan troglodytes), rhesus monkeys (Macaca mulatta), and stumptail monkeys (M. arctoides). Reciprocity correlations of interventions were determined while removing from the data the effects of several symmetrical relationship characteristics, that is, matrillineal kinship, proximity relations, and same-sex combination. It was considered likely that if significant reciprocity persisted after controlling for these characteristics, the reciprocity was based on cognitive mechanisms. Statistical significance was tested by means of recently developed matrix permutation procedures. All three species exhibited significant reciprocity with regard to beneficial interventions, even after controlling for symmetrical traits. Harmful interventions were, however, reciprocal among chimpanzees only. This species showed a “revenge system”, that is, if A often intervened against B, B did the same to A. In contrast, both macaque species showed significantly inversed reciprocity in their harmful interventions: if A often intervened against B, B rarely intervened against A. Further analysis indicates that the strict hierarchy of macaques prevents them from achieving complete reciprocity. Compared to chimpanzees, macaques rarely intervene against higher ranking group members. The observed contrast can be partially explained on the basis of differences in available space, as indicated by a comparison of indoor and outdoor living conditions for the chimpanzee colony. Yet, even when such spatial factors are taken into account, substantial behavior differences between chimpanzees and macaques remain.
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