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	Author	Scheibe, K.M.; Streich, W.J.
	Title	Annual Rhythm of Body Weight in Przewalski Horses (Equus ferus przewalskii)			Type	Journal Article
	Year	2003	Publication	Biological Rhythm Research	Abbreviated Journal
	Volume	34	Issue	4	Pages	383-395
	Keywords
	Abstract	The live-weight of female Przewalski horses in a semi-natural reserve has been recorded continuously over 6 years by means of an automatic weighing machine and automatic identification. Data were tested for cyclic as well as for linear trend effects and a mathematical model was developed. A clear annual rhythm of live-weight with the maximum in October was demonstrated. During the first 2 years of recording, the level of the annual rhythm was constant but, thereafter, different individual trends were found. Those individuals showing a steeply rising trend suffered from laminitis after three annual cycles. The periods of rising body weight corresponded to unusual mild winters. Animals newly introduced into the reserve from zoos showed a rise in their body weight in an adaptation phase. Furthermore, there was evidence for a phase adjustment of the annual rhythm. The results are discussed against a background of the theory of annual rhythms, and can be used as a basis for seasonal variations of feeding in zoos and for a re-evaluation of recommendations for population density in similar reserves. For reintroductions as well as for a transfer from zoos to semi-natural reserves, a longer adaptation phase is recommended.
	Address
	Corporate Author				Thesis
	Publisher	Taylor & Francis	Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0929-1016	ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number	Equine Behaviour @ team @			Serial	4991
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	Author	Rüegg J. C
	Title	Psychosomatik, Psychotherapie und Gehirn			Type	Book Whole
	Year	2003	Publication		Abbreviated Journal
	Volume		Issue		Pages
	Keywords
	Abstract
	Address
	Corporate Author				Thesis
	Publisher	Schattauer Verlag	Place of Publication	Stuttgart	Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN		ISBN	978-3794521500	Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number	Equine Behaviour @ team @			Serial	5016
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	Author	Wallner, B.; Brem, G.; Muller, M.; Achmann, R.
	Title	Fixed nucleotide differences on the Y chromosome indicate clear divergence between Equus przewalskii and Equus caballus			Type	Journal Article
	Year	2003	Publication	Animal Genetics	Abbreviated Journal	Anim Genet
	Volume	34	Issue	6	Pages	453-456
	Keywords	Animals; Base Sequence; DNA, Mitochondrial/genetics; Genetic Variation/genetics; Horses/classification/genetics; Male; Molecular Sequence Data; Phylogeny; Probability; Species Specificity; Y Chromosome/*genetics
	Abstract	The phylogenetic relationship between Equus przewalskii and E. caballus is often a matter of debate. Although these taxa have different chromosome numbers, they do not form monophyletic clades in a phylogenetic tree based on mtDNA sequences. Here we report sequence variation from five newly identified Y chromosome regions of the horse. Two fixed nucleotide differences on the Y chromosome clearly display Przewalski's horse and domestic horse as sister taxa. At both positions the Przewalski's horse haplotype shows the ancestral state, in common with the members of the zebra/ass lineage. We discuss the factors that may have led to the differences in mtDNA and Y-chromosomal observations.
	Address	Institut fur Tierzucht und Genetik, Veterinarmedizinische Universitat Wien, Veterinarplatz, Wien, Austria. wallner@i122server.vu-wien.ac.at
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language	English	Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0268-9146	ISBN		Medium
	Area		Expedition		Conference
	Notes	PMID:14687077			Approved	no
	Call Number	Equine Behaviour @ team @			Serial	5038
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	Author	Bowling, A.T.; Zimmermann, W.; Ryder, O.; Penado, C.; Peto, S.; Chemnick, L.; Yasinetskaya, N.; Zharkikh, T.
	Title	Genetic variation in Przewalski’s horses, with special focus on the last wild caught mare, 231 Orlitza III			Type	Journal Article
	Year	2003	Publication	Cytogenetic and Genome Research	Abbreviated Journal	Cytogenet Genome Res
	Volume	102	Issue	1-4	Pages	226-234
	Keywords
	Abstract
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	1424-8581	ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number	Equine Behaviour @ team @			Serial	5045
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	Author	Van Doorn G.S.; Hengeveld G.M.; Weissing F.J.
	Title	The Evolution of Social Dominance I: Two-player Models			Type	Journal Article
	Year	2003	Publication	Behavior	Abbreviated Journal	Behavior
	Volume	140	Issue	10	Pages	1305-1332
	Keywords
	Abstract	A difference in dominance rank is an often-used cue to resolve conflicts between two animals without escalated fights. At the group level, adherence to a dominance convention efficiently reduces the costs associated with conflicts, but from an individual's point of view, it is difficult to explain why a low ranking individual should accept its subordinate status. This is especially true if, as suggested by several authors, dominance not necessarily reflects differences in fighting ability but rather results from arbitrary historical asymmetries. According to this idea, rank differentiation emerges from behavioural strategies, referred to as winner and loser effects, in which winners of previous conflicts are more likely to win the current conflict, whereas the losers of previous conflicts are less likely to do so. In order to investigate whether dominance, based on such winner and loser effects, can be evolutionarily stable, we analyse a game theoretical model. The model focuses on an extreme case in which there are no differences in fighting ability between individuals at all. The only asymmetries that may arise between individuals are generated by the outcome of previous conflicts. By means of numerical analysis, we find alternative evolutionarily stable strategies, which all utilize these asymmetries for conventional conflict resolution. One class of these strategies is based on winner and loser effects, thus generating evolutionarily stable dominance relations even in the absence of differences in resource holding potential.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN		ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number	Equine Behaviour @ team @			Serial	5105
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	Author	Van Doorn G.S.; Hengeveld G.M.; Weissing F.J.
	Title	The Evolution of Social Dominance II: Multi-Player Models			Type	Journal Article
	Year	2003	Publication	Behavior	Abbreviated Journal	Behavior
	Volume	140	Issue	10	Pages	1333-1358
	Keywords
	Abstract	The social hierarchies observed in natural systems often show a high degree of transitivity. Transitive hierarchies do not only require rank differentiation within pairs of individuals but also a higher level ordering of relations within the group. Several authors have suggested that the formation of linear hierarchies at the group level is an emergent property of individual behavioural rules, referred to as winner and loser effects. Winner and loser effects occur if winners of previous conflicts are more likely to escalate the current conflict, whereas the losers of previous conflicts are less likely to do so. According to this idea, an individual's position in a hierarchy may not necessarily reflect its fighting ability, but may rather result from arbitrary historical asymmetries, in particular the history of victories and defeats. However, if this is the case, it is difficult to explain from an evolutionary perspective why a low ranking individual should accept its subordinate status. Here we present a game theoretical model to investigate whether winner and loser effects giving rise to transitive hierarchies can evolve and under which conditions they are evolutionarily stable. The main version of the model focuses on an extreme case in which there are no intrinsic differences in fighting ability between individuals. The only asymmetries that may arise between individuals are generated by the outcome of previous conflicts. We show that, at evolutionary equilibrium, these asymmetries can be utilized for conventional conflict resolution. Several evolutionarily stable strategies are based on winner and loser effects and these strategies give rise to transitive hierarchies.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN		ISBN		Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number	Equine Behaviour @ team @			Serial	5106
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	Author	Conradt, L.; Roper, T.J.
	Title	Group decision-making in animals			Type	Journal Article
	Year	2003	Publication	Nature	Abbreviated Journal	Nature
	Volume	421	Issue	6919	Pages	155-158
	Keywords	Animals; Behavior, Animal/physiology; Decision Making; Democracy; Group Processes; *Models, Biological; Population Density; Social Behavior
	Abstract	Groups of animals often need to make communal decisions, for example about which activities to perform, when to perform them and which direction to travel in; however, little is known about how they do so. Here, we model the fitness consequences of two possible decision-making mechanisms: 'despotism' and 'democracy'. We show that under most conditions, the costs to subordinate group members, and to the group as a whole, are considerably higher for despotic than for democratic decisions. Even when the despot is the most experienced group member, it only pays other members to accept its decision when group size is small and the difference in information is large. Democratic decisions are more beneficial primarily because they tend to produce less extreme decisions, rather than because each individual has an influence on the decision per se. Our model suggests that democracy should be widespread and makes quantitative, testable predictions about group decision-making in non-humans.
	Address	School of Biological Sciences, University of Sussex, Brighton BN1 9QG, UK. l.conradt@sussex.ac.uk
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language	English	Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0028-0836	ISBN		Medium
	Area		Expedition		Conference
	Notes	PMID:12520299			Approved	no
	Call Number	Equine Behaviour @ team @			Serial	5136
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	Author	Rands, S.A.; Cowlishaw, G.; Pettifor, R.A.; Rowcliffe, J.M.; Johnstone, R.A.
	Title	Spontaneous emergence of leaders and followers in foraging pairs			Type	Journal Article
	Year	2003	Publication	Nature	Abbreviated Journal	Nature
	Volume	423	Issue	6938	Pages	432-434
	Keywords	Animals; Energy Metabolism; Food; Food Chain; Models, Biological; Motor Activity; Social Behavior; Time Factors
	Abstract	Animals that forage socially often stand to gain from coordination of their behaviour. Yet it is not known how group members reach a consensus on the timing of foraging bouts. Here we demonstrate a simple process by which this may occur. We develop a state-dependent, dynamic game model of foraging by a pair of animals, in which each individual chooses between resting or foraging during a series of consecutive periods, so as to maximize its own individual chances of survival. We find that, if there is an advantage to foraging together, the equilibrium behaviour of both individuals becomes highly synchronized. As a result of this synchronization, differences in the energetic reserves of the two players spontaneously develop, leading them to adopt different behavioural roles. The individual with lower reserves emerges as the 'pace-maker' who determines when the pair should forage, providing a straightforward resolution to the problem of group coordination. Moreover, the strategy that gives rise to this behaviour can be implemented by a simple 'rule of thumb' that requires no detailed knowledge of the state of other individuals.
	Address	Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK. s.rands@zoo.cam.ac.uk
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language	English	Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0028-0836	ISBN		Medium
	Area		Expedition		Conference
	Notes	PMID:12761547			Approved	no
	Call Number	Equine Behaviour @ team @			Serial	5138
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	Author	Camazine, S.; Deneubourg, J.L.; Franks, N.R.; Sneyd, J.; Theraula, G.; Bonabeau, E.
	Title	Self-Organization in Biological Systems			Type	Book Whole
	Year	2003	Publication		Abbreviated Journal
	Volume		Issue		Pages
	Keywords
	Abstract
	Address
	Corporate Author				Thesis
	Publisher	Princeton University Press	Place of Publication	Princeton	Editor
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN		ISBN	978-0691116242	Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number	Equine Behaviour @ team @			Serial	5143
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	Author	Couzin, I.D.; Krause, J.
	Title	Self-Organization and Collective Behavior in Vertebrates			Type	Book Chapter
	Year	2003	Publication	Advances in the Study of Behavior	Abbreviated Journal
	Volume	32	Issue		Pages	1-75
	Keywords
	Abstract
	Address
	Corporate Author				Thesis
	Publisher	Academic Press	Place of Publication		Editor	Peter J. B. Slater, J.S.R., Charles T. Snowdon and Timothy J. Roper
	Language		Summary Language		Original Title
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN		ISBN	0065-3454	Medium
	Area		Expedition		Conference
	Notes				Approved	no
	Call Number	Equine Behaviour @ team @			Serial	5144
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