Zimmermann, W., & Zimmermann, M. (2012). Operation unterm Kranichhimmel. In K. Krueger (Ed.), Proceedings of the 2. International Equine Science Meeting (Vol. in press). Wald: Xenophon Publishing.
Abstract: Auf dem herbstlichen Zug in den Süden rasten bis zu 80 000 Kraniche im Hortobágy Nationalpark im Osten Ungarns. Das einst von Wildtieren besiedelte Gebiet ist heute eine Kulturlandschaft aus Feldern und Weiden, wo seltene Haustierrassen wie Zackelschaf, Graurind und Noniuspferde grasen, die von Hirten mit ihren Hunden gehütet werden. Die noch erhaltenen Steppengebiete zeichnen sich durch eine große Vielfalt in Flora und Fauna aus. Sie sollen möglichst wenig betreten werden, damit vor allem die bodenbrütenden Vögel, wie z.B. die seltene Großtrappe nicht gestört werden. Deshalb wurde die Kernzone – das Pentezug-Gebiet (2400 ha) – mit Przewalskipferden und „Auerochsen“ zur natürlichen Beweidung besetzt. Bereits in den ersten Jahren fiel es auf, dass das Rind deutlich schlechter an die kalte Jahreszeit angepasst ist als das Wildpferd. Deshalb wurden beide Arten besendert, um Körpertemperatur und Herzschlagfrequenz zu messen. Außerdem sollten Gras- und Kotanalysen Aufschluss über die Unterschiede in der Futterverwertbarkeit liefern.
Der Film zeigt die chirurgische Arbeit im Feld und vermittelt einen Eindruck über die Funktion der Sender. Außerdem werden die neuen Bemühungen vorgestellt, aus dem Heckrind eine robuste Rinderrasse zu züchten, die dem Auerochsen noch ähnlicher sieht.
Ein Ziel der Untersuchungen war es, die klimatischen Grenzen zu erkennen, in denen die „Auerochsen“ einen Winter ohne Zufütterung überleben können. Diese Rinderrasse wird verstärkt zur Beweidung in Naturschutzgebieten eingesetzt, ihren Bedürfnissen wird aber nicht immer Rechnung getragen.
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Zimen, E. (1975). Social dynamics of the wolf pack. In M. W. Fox (Ed.), The wild canids (pp. 336–362). New York: Van Nostrand Reinhold.
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Ziegler, W. H. (1976). [Endocrinological studies in arterial hypertension. Search for phaeochromocytoma]. Schweiz Med Wochenschr, 106(34), 1148–1150.
Abstract: Elevated urinary catecholamines and their metabolites are the only findings which confirm the presence of pheochromocytoma. This examination is of particular interest if carried out in urine produced after spontaneous hypertensive episodes. Pharmacologic tests when carried out under standard conditions have proven to be a reliable aid in cases of suspected pheochromocytoma. Roentgenographic studies, determination of local plasma catecholamine concentrations and blood volume control should be undertaken in these patients before surgical procedure.
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Ziccardi F,. (1970). The african wild ass: Part I. Afr Wild Life, 24, 202–208.
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Ziccardi F,. (1970). The african wild ass: Part II. Afr Wild Life, 24, 287–292.
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Zhou, W. - X., Sornette, D., Hill, R. A., & Dunbar, R. I. M. (2005). Discrete hierarchical organization of social group sizes. Proc Biol Sci, 272(1561), 439–444.
Abstract: The 'social brain hypothesis' for the evolution of large brains in primates has led to evidence for the coevolution of neocortical size and social group sizes, suggesting that there is a cognitive constraint on group size that depends, in some way, on the volume of neural material available for processing and synthesizing information on social relationships. More recently, work on both human and non-human primates has suggested that social groups are often hierarchically structured. We combine data on human grouping patterns in a comprehensive and systematic study. Using fractal analysis, we identify, with high statistical confidence, a discrete hierarchy of group sizes with a preferred scaling ratio close to three: rather than a single or a continuous spectrum of group sizes, humans spontaneously form groups of preferred sizes organized in a geometrical series approximating 3-5, 9-15, 30-45, etc. Such discrete scale invariance could be related to that identified in signatures of herding behaviour in financial markets and might reflect a hierarchical processing of social nearness by human brains.
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Zharkikh, T. L., & Andersen, L. (2009). Behaviour of Bachelor Males of the Przewalski Horse (Equus ferus przewalskii) at the Reserve Askania Nova. Zoologische Garten, 78(5-6), 282–299.
Abstract: The aim of this study was to investigate social relationships between Przewalski horses at a high density in a bachelor group housed in a 3.5-ha enclosure. The group consisted of 16 males aged 5 to 16. Behavioural data were collected during 18 days, total 216 h. Fifteen minute focal animal sampling was used; each horse was observed three times a day for a total of 45 min. The occurrence of 25 behaviours was recorded, and group spacing behaviour was studied using nearest neighbour recordings. The group divided into four subgroups; this supports earlier findings of bachelor groups (n>=10) dividing into two or more subgroups if they included several males aged >5 years. The total frequency of social interactions was 14.6±1.1 h-1. Although the density of the group in this study was higher than in other zoos, the males interacted agonistically only 3.6 h-1. The most frequently observed social behaviour categories were friendly interactions. This study shows possibilities to use some investigative behaviours (marking, flehmen, olfactory investigation, etc.) as indicators of social status of animals in a group.
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Zhao, C. J., Qin, Y. H., Lee, X. H., & Wu, C. (2006). Molecular and cytogenetic paternity testing of a male offspring of a hinny. J Anim Breed Genet, 123(6), 403–405.
Abstract: An alleged male foal of a female mule, whose sire and grandparents were unknown, was identified for its pedigree. Parentage testing was conducted by comparing polymorphism of 12 microsatellite DNA sites and mitochondrial D-loop sequences of the male foal and the female mule. Both the sequence analysis of species-specific DNA fragments and a cytogenetic analysis were performed to identify the species of the foal and its parents. The results showed that the alleged female mule is actually a hinny, and the male foal, which possesses 62 chromosomes, qualifies as an offspring of the female hinny and a jack donkey.
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Zhang, Y., Cao, Q. S., Rubenstein, D. I., Zang, S., Songer, M., Leimgruber, P., et al. (2015). Water Use Patterns of Sympatric Przewalski's Horse and Khulan: Interspecific Comparison Reveals Niche Differences. Plos One, 10(7), e0132094.
Abstract: Acquiring water is essential for all animals, but doing so is most challenging for desert-living animals. Recently Przewalski's horse has been reintroduced to the desert area in China where the last wild surviving member of the species was seen before it vanished from China in the1960s. Its reintroduction placed it within the range of a close evolutionary relative, the con-generic Khulan. Determining whether or not these two species experience competition and whether or not such competition was responsible for the extinction of Przewalski's horses in the wild over 50 years ago, requires identifying the fundamental and realized niches of both species. We remotely monitored the presence of both species at a variety of water points during the dry season in Kalamaili Nature Reserve, Xinjiang, China. Przewalski's horses drank twice per day mostly during daylight hours at low salinity water sources while Khulans drank mostly at night usually at high salinity water points or those far from human residences. Spatial and temporal differences in water use enables coexistence, but suggest that Przewalski's horses also restrict the actions of Khulan. Such differences in both the fundamental and realized niches were associated with differences in physiological tolerances for saline water and human activity as well as differences in aggression and dominance.
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Zhang, T. - Y., Parent, C., Weaver, I., & Meaney, M. J. (2004). Maternal programming of individual differences in defensive responses in the rat. Ann N Y Acad Sci, 1032, 85–103.
Abstract: This paper describes the results of a series of studies showing that variations in mother-pup interactions program the development of individual differences in behavioral and endocrine stress responses in the rat. These effects are associated with altered expression of genes in brain regions, such as the amygdala, hippocampus, and hypothalamus, that regulate the expression of stress responses. Studies from evolutionary biology suggest that such “maternal effects” are common and often associated with variations in the quality of the maternal environment. Together these findings suggest an epigenetic process whereby the experience of the mother alters the nature of the parent-offspring interactions and thus the phenotype of the offspring.
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