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	Author	Santamaria, S.; Bobbert, M.E.; Back, W.; Barneveld, A.; van Weeren, P.R.
	Title	Variation in free jumping technique within and among horses with little experience in show jumping			Type	Journal Article
	Year	2004	Publication	American Journal of Veterinary Research	Abbreviated Journal	Am J Vet Res
	Volume	65	Issue	7	Pages	938-944
	Keywords	Acceleration; Analysis of Variance; Animals; Biomechanics; Forelimb/physiology; Gait/physiology; Hindlimb/physiology; Horses/physiology; Locomotion/physiology; Models, Biological; Video Recording
	Abstract	OBJECTIVE: To quantify variation in the jumping technique within and among young horses with little jumping experience, establish relationships between kinetic and kinematic variables, and identify a limited set of variables characteristic for detecting differences in jumping performance among horses. ANIMALS: Fifteen 4-year-old Dutch Warmblood horses. PROCEDURE: The horses were raised under standardized conditions and trained in accordance with a fixed protocol for a short period. Subsequently, horses were analyzed kinematically during free jumping over a fence with a height of 1.05 m. RESULTS: Within-horse variation in all variables that quantified jumping technique was smaller than variation among horses. However, some horses had less variation than others. Height of the center of gravity (CG) at the apex of the jump ranged from 1.80 to 2.01 m among horses; this variation could be explained by the variation in vertical velocity of the CG at takeoff (r, 0.78). Horses that had higher vertical velocity at takeoff left the ground and landed again farther from the fence, had shorter push-off phases for the forelimbs and hind limbs, and generated greater vertical acceleration of the CG primarily during the hind limb push-off. However, all horses cleared the fence successfully, independent of jumping technique. CONCLUSIONS AND CLINICAL RELEVANCE: Each horse had its own jumping technique. Differences among techniques were characterized by variations in the vertical velocity of the CG at takeoff. It must be determined whether jumping performance later in life can be predicted from observing free jumps of young horses.
	Address	Department of Equine Sciences, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 12, NL-3584 CM Utrecht, The Netherlands
	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	0002-9645	ISBN		Medium
	Area		Expedition		Conference
	Notes	PMID:15281652			Approved	no
	Call Number	Equine Behaviour @ team @			Serial	3772
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	Author	Dubois, F.; Giraldeau, L.-A.; Hamilton, I.M.; Grant, J.W.A.; Lefebvre, L.
	Title	Distraction sneakers decrease the expected level of aggression within groups: a game-theoretic model			Type	Journal Article
	Year	2004	Publication	The American Naturalist	Abbreviated Journal	Am Nat
	Volume	164	Issue	2	Pages	E32-45
	Keywords	Aggression; Animals; Behavior, Animal/physiology; Columbidae/physiology; Competitive Behavior; Cooperative Behavior; Game Theory; Hawks/*physiology; Models, Biological
	Abstract	Hawk-dove games have been extensively used to predict the conditions under which group-living animals should defend their resources against potential usurpers. Typically, game-theoretic models on aggression consider that resource defense may entail energetic and injury costs. However, intruders may also take advantage of owners who are busy fighting to sneak access to unguarded resources, imposing thereby an additional cost on the use of the escalated hawk strategy. In this article we modify the two-strategy hawk-dove game into a three-strategy hawk-dove-sneaker game that incorporates a distraction-sneaking tactic, allowing us to explore its consequences on the expected level of aggression within groups. Our model predicts a lower proportion of hawks and hence lower frequencies of aggressive interactions within groups than do previous two-strategy hawk-dove games. The extent to which distraction sneakers decrease the frequency of aggression within groups, however, depends on whether they search only for opportunities to join resources uncovered by other group members or for both unchallenged resources and opportunities to usurp.
	Address	Departement des Sciences Biologiques, Universite du Quebec a Montreal, Case postale 8888 Succursale Centre-Ville, Montreal, Quebec H3C 3P8, Canada. frede_dubois@yahoo.fr
	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	1537-5323	ISBN		Medium
	Area		Expedition		Conference
	Notes	PMID:15278850			Approved	no
	Call Number				Serial	2130
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	Author	Brilot, B.O.; Johnstone, R.A.
	Title	The limits to cost-free signalling of need between relatives			Type	Journal Article
	Year	2003	Publication	Proceedings. Biological sciences / The Royal Society	Abbreviated Journal	Proc Biol Sci
	Volume	270	Issue	1519	Pages	1055-1060
	Keywords	Animal Communication; Animals; Birds/physiology; Models, Biological; Social Behavior
	Abstract	Theoretical models have demonstrated the possibility of stable cost-free signalling of need between relatives. The stability of these cost-free equilibria depends on the indirect fitness cost of cheating and deceiving a donor into giving away resources. We show that this stability is highly sensitive to the distribution of need among signallers and receivers. In particular, cost-free signalling is likely to prove stable only if there is very large variation in need (such that the least-needy individuals stand to gain much less than the most-needy individuals from additional resources). We discuss whether these conditions are likely to be found in altricial avian breeding systems--the most intensively studied instance of signalling of need between relatives. We suggest that cost-free signalling is more likely to prove stable and will provide parents with more information during the earlier phases of chick growth, when parents can more easily meet the demands of a brood (and chicks are more likely to reach satiation). Later, informative yet cost-free signalling is unlikely to persist.
	Address	Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK. bob21@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	0962-8452	ISBN		Medium
	Area		Expedition		Conference
	Notes	PMID:12803895			Approved	no
	Call Number	refbase @ user @			Serial	558
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	Author	Reimers, M.; Schwarzenberger, F.; Preuschoft, S.
	Title	Rehabilitation of research chimpanzees: stress and coping after long-term isolation			Type	Journal Article
	Year	2007	Publication	Hormones and Behavior	Abbreviated Journal	Horm Behav
	Volume	51	Issue	3	Pages	428-435
	Keywords	Adaptation, Psychological/physiology; Animals; Animals, Laboratory; Exploratory Behavior; Hydrocortisone/analysis/metabolism; Male; Models, Biological; Pan troglodytes; Social Dominance; Social Environment; Social Isolation/psychology; Stress/*rehabilitation/veterinary; Time
	Abstract	We report on the permanent retirement of chimpanzees from biomedical research and on resocialization after long-term social isolation. Our aim was to investigate to what extent behavioral and endocrine measures of stress in deprived laboratory chimpanzees can be improved by a more species-typical social life style. Personality in terms of novelty responses, social dominance after resocialization and hormonal stress susceptibility were affected by the onset of maternal separation of infant chimpanzees and duration of deprivation. Chimpanzees, who were separated from their mothers at a younger age and kept in isolation for more years appeared to be more timid personalities, less socially active, less dominant and more susceptible to stress, as compared to chimpanzees with a less severe deprivation history. However, permanent retirement from biomedical research in combination with therapeutic resocialization maximizing chimpanzees' situation control resulted in reduced fecal cortisol metabolite levels. Our results indicate that chimpanzees can recover from severe social deprivation, and may experience resocialization as less stressful than solitary housing.
	Address	Department of Natural Sciences, Institute of Biochemistry, University of Veterinary Medicine, Veterinarplatz 1, 1210 Vienna, Austria. reimers@wild-vet.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	0018-506X	ISBN		Medium
	Area		Expedition		Conference
	Notes	PMID:17292368			Approved	no
	Call Number	Equine Behaviour @ team @			Serial	4188
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	Author	Santamaria, S.; Bobbert, M.F.; Back, W.; Barneveld, A.; van Weeren, P.R.
	Title	Effect of early training on the jumping technique of horses			Type	Journal Article
	Year	2005	Publication	American Journal of Veterinary Research	Abbreviated Journal	Am J Vet Res
	Volume	66	Issue	3	Pages	418-424
	Keywords	Age Factors; Analysis of Variance; Animals; Biomechanics; Forelimb/physiology; Gait/physiology; Hindlimb/physiology; Horses/growth & development/physiology; Locomotion/physiology; Models, Biological; Physical Conditioning, Animal/methods
	Abstract	OBJECTIVE: To investigate the effects of early training for jumping by comparing the jumping technique of horses that had received early training with that of horses raised conventionally. ANIMALS: 40 Dutch Warmblood horses. PROCEDURE: The horses were analyzed kinematically during free jumping at 6 months of age. Subsequently, they were allocated into a control group that was raised conventionally and an experimental group that received 30 months of early training starting at 6 months of age. At 4 years of age, after a period of rest in pasture and a short period of training with a rider, both groups were analyzed kinematically during free jumping. Subsequently, both groups started a 1-year intensive training for jumping, and at 5 years of age, they were again analyzed kinematically during free jumping. In addition, the horses competed in a puissance competition to test maximal performance. RESULTS: Whereas there were no differences in jumping technique between experimental and control horses at 6 months of age, at 4 years, the experimental horses jumped in a more effective manner than the control horses; they raised their center of gravity less yet cleared more fences successfully than the control horses. However, at 5 years of age, these differences were not detected. Furthermore, the experimental horses did not perform better than the control horses in the puissance competition. CONCLUSIONS AND CLINICAL RELEVANCE: Specific training for jumping of horses at an early age is unnecessary because the effects on jumping technique and jumping capacity are not permanent.
	Address	Department of Equine Sciences, Faculty of Veterinary Medicine, Utrecht University, NL-3584 CM Utrecht, The Netherlands
	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	0002-9645	ISBN		Medium
	Area		Expedition		Conference
	Notes	PMID:15822585			Approved	no
	Call Number	Equine Behaviour @ team @			Serial	4037
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	Author	Cameron, E.Z.
	Title	Facultative adjustment of mammalian sex ratios in support of the Trivers-Willard hypothesis: evidence for a mechanism			Type	Journal Article
	Year	2004	Publication	Proceedings. Biological sciences / The Royal Society	Abbreviated Journal	Proc Biol Sci
	Volume	271	Issue	1549	Pages	1723-1728
	Keywords	Age Factors; Animals; Body Constitution; Evolution; Female; Glucose/metabolism/physiology; Litter Size; Male; Mammals/physiology; Models, Biological; Reproduction/physiology; Seasons; Sex Factors; Sex Ratio; Time Factors
	Abstract	Evolutionary theory predicts that mothers of different condition should adjust the birth sex ratio of their offspring in relation to future reproductive benefits. Published studies addressing variation in mammalian sex ratios have produced surprisingly contradictory results. Explaining the source of such variation has been a challenge for sex-ratio theory, not least because no mechanism for sex-ratio adjustment is known. I conducted a meta-analysis of previous mammalian sex-ratio studies to determine if there are any overall patterns in sex-ratio variation. The contradictory nature of previous results was confirmed. However, studies that investigated indices of condition around conception show almost unanimous support for the prediction that mothers in good condition bias their litters towards sons. Recent research on the role of glucose in reproductive functioning have shown that excess glucose favours the development of male blastocysts, providing a potential mechanism for sex-ratio variation in relation to maternal condition around conception. Furthermore, many of the conflicting results from studies on sex-ratio adjustment would be explained if glucose levels in utero during early cell division contributed to the determination of offspring sex ratios.
	Address	Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, Pretoria 0002, South Africa. ezcameron@zoology.up.ac.za
	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	0962-8452	ISBN		Medium
	Area		Expedition		Conference
	Notes	PMID:15306293			Approved	no
	Call Number	refbase @ user @			Serial	413
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	Author	Wolf, M.; van Doorn, G.S.; Leimar, O.; Weissing, F.J.
	Title	Life-history trade-offs favour the evolution of animal personalities			Type	Journal Article
	Year	2007	Publication	Nature	Abbreviated Journal	Nature
	Volume	447	Issue	7144	Pages	581-584
	Keywords	Aggression/physiology/psychology; Animals; Behavior, Animal/physiology; Evolution; Exploratory Behavior/physiology; Models, Biological; Personality/*physiology; Predatory Behavior/physiology; Reproduction/physiology; Risk-Taking; Selection (Genetics)
	Abstract	In recent years evidence has been accumulating that personalities are not only found in humans but also in a wide range of other animal species. Individuals differ consistently in their behavioural tendencies and the behaviour in one context is correlated with the behaviour in multiple other contexts. From an adaptive perspective, the evolution of animal personalities is still a mystery, because a more flexible structure of behaviour should provide a selective advantage. Accordingly, many researchers view personalities as resulting from constraints imposed by the architecture of behaviour (but see ref. 12). In contrast, we show here that animal personalities can be given an adaptive explanation. Our argument is based on the insight that the trade-off between current and future reproduction often results in polymorphic populations in which some individuals put more emphasis on future fitness returns than others. Life-history theory predicts that such differences in fitness expectations should result in systematic differences in risk-taking behaviour. Individuals with high future expectations (who have much to lose) should be more risk-averse than individuals with low expectations. This applies to all kinds of risky situations, so individuals should consistently differ in their behaviour. By means of an evolutionary model we demonstrate that this basic principle results in the evolution of animal personalities. It simultaneously explains the coexistence of behavioural types, the consistency of behaviour through time and the structure of behavioural correlations across contexts. Moreover, it explains the common finding that explorative behaviour and risk-related traits like boldness and aggressiveness are common characteristics of animal personalities.
	Address	Theoretical Biology Group, Centre for Ecological and Evolutionary Studies, University of Groningen, Kerklaan 30, 9751 NN Haren, The Netherlands
	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	1476-4687	ISBN		Medium
	Area		Expedition		Conference
	Notes	PMID:17538618			Approved	no
	Call Number	Equine Behaviour @ team @			Serial	4098
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	Author	Bell, A.M.
	Title	Evolutionary biology: animal personalities			Type
	Year	2007	Publication	Nature	Abbreviated Journal	Nature
	Volume	447	Issue	7144	Pages	539-540
	Keywords	Aggression/physiology/psychology; Animals; Behavior, Animal/physiology; Evolution; Humans; Models, Biological; Personality/genetics/physiology; Reproduction/genetics/physiology; Risk-Taking; Selection (Genetics)
	Abstract
	Address
	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	1476-4687	ISBN		Medium
	Area		Expedition		Conference
	Notes	PMID:17538607			Approved	no
	Call Number	Equine Behaviour @ team @			Serial	4099
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	Author	Grosenick, L.; Clement, T.S.; Fernald, R.D.
	Title	Fish can infer social rank by observation alone			Type	Journal Article
	Year	2007	Publication	Nature	Abbreviated Journal	Nature
	Volume	445	Issue	7126	Pages	429-432
	Keywords	Aggression/physiology; Animals; Cognition/physiology; Female; Fishes/physiology; Learning/physiology; Male; Models, Biological; Social Dominance; Territoriality
	Abstract	Transitive inference (TI) involves using known relationships to deduce unknown ones (for example, using A > B and B > C to infer A > C), and is thus essential to logical reasoning. First described as a developmental milestone in children, TI has since been reported in nonhuman primates, rats and birds. Still, how animals acquire and represent transitive relationships and why such abilities might have evolved remain open problems. Here we show that male fish (Astatotilapia burtoni) can successfully make inferences on a hierarchy implied by pairwise fights between rival males. These fish learned the implied hierarchy vicariously (as 'bystanders'), by watching fights between rivals arranged around them in separate tank units. Our findings show that fish use TI when trained on socially relevant stimuli, and that they can make such inferences by using indirect information alone. Further, these bystanders seem to have both spatial and featural representations related to rival abilities, which they can use to make correct inferences depending on what kind of information is available to them. Beyond extending TI to fish and experimentally demonstrating indirect TI learning in animals, these results indicate that a universal mechanism underlying TI is unlikely. Rather, animals probably use multiple domain-specific representations adapted to different social and ecological pressures that they encounter during the course of their natural lives.
	Address	Department of Biological Sciences, Stanford University, Stanford, California, 94305, USA. logang@stanford.edu
	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	1476-4687	ISBN		Medium
	Area		Expedition		Conference
	Notes	PMID:17251980			Approved	no
	Call Number	refbase @ user @			Serial	600
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	Author	Galloux, P.; Barrey, E.
	Title	Components of the total kinetic moment in jumping horses			Type	Journal Article
	Year	1997	Publication	Equine Veterinary Journal. Supplement	Abbreviated Journal	Equine Vet J Suppl
	Volume		Issue	23	Pages	41-44
	Keywords	Algorithms; Animals; Exertion/physiology; Female; Gravitation; Horses/physiology; Kinetics; Locomotion/physiology; Male; Models, Biological; Movement/physiology; Video Recording
	Abstract	Thirty horses were filmed with a panning camera operating at 50 frames/s as they jumped over a 1.20 x 1.20 m fence. The markers of 9 joints on the horse and 7 joints on the rider were tracked in 2D with the TrackEye system. The centre of gravity and moment of inertia of each segment were calculated using a geometric algorithm and a cylindric model, respectively. The kinetic moment of each part of the horse was calculated after filtering, and resampling of data. This method showed the relative contribution of each body segment to the body overall rotation during the take-off, jump and landing phases. It was found that the trunk, hindlimbs and head-neck had the greatest influence. The coordination between the motion of the body segments allowed the horse to control its angular speed of rotation over the fence. This remained nearly constant during the airborne phase (120 +/- 5 degrees/s). During the airborne phase, the kinetic moment was constant because its value was equal to the moment of the external forces (722 +/- 125 kg x m2/s).
	Address	Ecole Nationale d'Equitation, Terrefort, Saumur, France
	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		ISBN		Medium
	Area		Expedition		Conference
	Notes	PMID:9354287			Approved	no
	Call Number	Equine Behaviour @ team @			Serial	3797
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