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	Author	Bobbert, M.F.; Santamaria, S.
	Title	Contribution of the forelimbs and hindlimbs of the horse to mechanical energy changes in jumping			Type	Journal Article
	Year	2005	Publication	The Journal of Experimental Biology	Abbreviated Journal	J Exp Biol
	Volume	208	Issue	2	Pages	249-260
	Keywords	Animals; Biomechanics; Forelimb/physiology; Hindlimb/physiology; Horses/physiology; Locomotion/physiology; Muscle, Skeletal/*physiology; Time Factors
	Abstract	The purpose of the present study was to gain more insight into the contribution of the forelimbs and hindlimbs of the horse to energy changes during the push-off for a jump. For this purpose, we collected kinematic data at 240 Hz from 23 5-year-old Warmbloods (average mass: 595 kg) performing free jumps over a 1.15 m high fence. From these data, we calculated the changes in mechanical energy and the changes in limb length and joint angles. The force carried by the forelimbs and the amount of energy stored was estimated from the distance between elbow and hoof, assuming that this part of the leg behaved as a linear spring. During the forelimb push, the total energy first decreased by 3.2 J kg(-1) and then increased again by 4.2 J kg(-1) to the end of the forelimb push. At the end of the forelimb push, the kinetic energy due to horizontal velocity of the centre of mass was 1.6 J kg(-1) less than at the start, while the effective energy (energy contributing to jump height) was 2.3 J kg(-1) greater. It was investigated to what extent these changes could involve passive spring-like behaviour of the forelimbs. The amount of energy stored and re-utilized in the distal tendons during the forelimb push was estimated to be on average 0.4 J kg(-1) in the trailing forelimb and 0.23 J kg(-1) in the leading forelimb. This means that a considerable amount of energy was first dissipated and subsequently regenerated by muscles, with triceps brachii probably being the most important contributor. During the hindlimb push, the muscles of the leg were primarily producing energy. The total increase in energy was 2.5 J kg(-1) and the peak power output amounted to 71 W kg(-1).
	Address	Institute for Fundamental and Clinical Human Movement Sciences, Vrije Universiteit, van der Boechorstraat 9, NL-1081 BT Amsterdam, The Netherlands. MFBobbert@fbw.vu.nl
	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	0022-0949	ISBN		Medium
	Area		Expedition		Conference
	Notes	PMID:15634844			Approved	no
	Call Number				Serial	1895
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	Author	Robert, N.; Walzer, C.; Ruegg, S.R.; Kaczensky, P.; Ganbaatar, O.; Stauffer, C.
	Title	Pathologic findings in reintroduced Przewalski's horses (Equus caballus przewalskii) in southwestern Mongolia			Type	Journal Article
	Year	2005	Publication	Journal of zoo and Wildlife Medicine : Official Publication of the American Association of Zoo Veterinarians	Abbreviated Journal	J Zoo Wildl Med
	Volume	36	Issue	2	Pages	273-285
	Keywords	Animals; Babesiosis/epidemiology/pathology/veterinary; Cause of Death; Conservation of Natural Resources; Disease Susceptibility/veterinary; Environment; Female; Food Chain; Horse Diseases/epidemiology/pathology; Horses; Male; Mongolia/epidemiology; Streptococcal Infections/epidemiology/pathology/veterinary; Streptococcus equi; Theileriasis/*epidemiology/pathology; Weather
	Abstract	The Przewalski's horse (Equus caballus przewalskii) was extinct in the wild by the mid 1960s. The species has survived because of captive breeding only. The Takhin Tal reintroduction project is run by the International Takhi Group; it is one of two projects reintroducing horses to the wild in Mongolia. In 1997 the first harem group was released. The first foals were successfully raised in the wild in 1999. Currently, 63 Przewalski's horses live in Takhin Tal. Little information exists on causes of mortality before the implementation of a disease-monitoring program in 1998. Since 1999, all dead horses recovered (n = 28) have been examined and samples collected and submitted for further investigation. Equine piroplasmosis, a tick-transmitted disease caused by Babesia caballi or Theileria equi, is endemic in Takhin Tal and was identified as the cause of death of four stallions and one stillborn foal. In December 2000, wolf predation was implicated in the loss of several Przewalski's horses. However, thorough clinical, pathologic, and bacteriologic investigations performed on dead and surviving horses of this group revealed lesions compatible with strangles. The extreme Mongolian winter of 2000-2001 is thought to have most probably weakened the horses, making them more susceptible to opportunistic infection and subsequent wolf predation. Other occasional causes of death since 1999 were trauma, exhaustion, wasting, urolithiasis, pneumonia, abortion, and stillbirth. The pathologic examination of the Przewalski's horses did not result in a definitive diagnosis in each case. Several disease factors were found to be important in the initial phase of the reintroduction, which could potentially jeopardize the establishment of a self-sustaining population.
	Address	Center for Fish and Wildlife Health, Institute of Animal Pathology, University of Berne, Langgass-Strasse 122, CH-3001 Berne, Switzerland
	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	1042-7260	ISBN		Medium
	Area		Expedition		Conference
	Notes	PMID:17323569			Approved	no
	Call Number				Serial	2023
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	Author	Dumont, B.; Boissy, A.; Achard, C.; Sibbald, A.M.; Erhard, H.W.
	Title	Consistency of animal order in spontaneous group movements allows the measurement of leadership in a group of grazing heifers			Type	Journal Article
	Year	2005	Publication	Applied Animal Behaviour Science	Abbreviated Journal	Appl. Anim. Behav. Sci.
	Volume	95	Issue	1-2	Pages	55-66
	Keywords	Cattle; Grazing; Leadership; Movement order; Walking
	Abstract	The term `leadership' has been used in several different senses, resulting in very different ways of identifying leaders and apparently inconsistent conclusions on how leadership is determined in herbivores. We therefore propose the following definitions: (i) a leader is the individual that is consistently the one who initiates long-distance, spontaneous group movements toward a new feeding site and (ii) long-distance spontaneous group movements are movements which happen when an animal changes activity and location and is immediately followed by a similar change in activity and location by other members of the group. Using these definitions, we tested for consistency of movement order across time and situation within a group of fifteen 2-year-old heifers. We found that the same individual was recorded as the very first animal in 48% of movements toward a new feeding site and could therefore be identified as the `leader'. We also showed that movement order when the animals entered an experimental plot, or progressed slowly through the field during a grazing bout, did not produce the same result. This method, which enables us to identify leaders in groups of animals at pasture, should improve our knowledge of how leadership is determined in grazing herbivores.
	Address
	Corporate Author				Thesis
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	Notes				Approved	no
	Call Number	Equine Behaviour @ team @ room B 3.029			Serial	2027
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	Author	Dall, S.R.X.; Giraldeau, L.-A.; Olsson, O.; McNamara, J.M.; Stephens, D.W.
	Title	Information and its use by animals in evolutionary ecology			Type	Journal Article
	Year	2005	Publication	Trends in Ecology & Evolution (Personal Edition)	Abbreviated Journal	Trends Ecol Evol
	Volume	20	Issue	4	Pages	187-193
	Keywords
	Abstract	Information is a crucial currency for animals from both a behavioural and evolutionary perspective. Adaptive behaviour relies upon accurate estimation of relevant ecological parameters; the better informed an individual, the better it can develop and adjust its behaviour to meet the demands of a variable world. Here, we focus on the burgeoning interest in the impact of ecological uncertainty on adaptation, and the means by which it can be reduced by gathering information, from both 'passive' and 'responsive' sources. Our overview demonstrates the value of adopting an explicitly informational approach, and highlights the components that one needs to develop useful approaches to studying information use by animals. We propose a quantitative framework, based on statistical decision theory, for analysing animal information use in evolutionary ecology. Our purpose is to promote an integrative approach to studying information use by animals, which is itself integral to adaptive animal behaviour and organismal biology.
	Address	Centre for Ecology and Conservation, University of Exeter in Cornwall, Tremough Campus, Penryn, UK, TR10 9EZ. sashadall@iname.com
	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	0169-5347	ISBN		Medium
	Area		Expedition		Conference
	Notes	PMID:16701367			Approved	no
	Call Number				Serial	2128
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	Author	Barrett, L.; Henzi, P.
	Title	The social nature of primate cognition			Type	Journal Article
	Year	2005	Publication	Proceedings. Biological Sciences / The Royal Society	Abbreviated Journal	Proc Biol Sci
	Volume	272	Issue	1575	Pages	1865-1875
	Keywords	Animals; Brain/anatomy & histology/physiology; Cognition/physiology; Evolution; Intelligence/physiology; Primates/physiology; Social Behavior
	Abstract	The hypothesis that the enlarged brain size of the primates was selected for by social, rather than purely ecological, factors has been strongly influential in studies of primate cognition and behaviour over the past two decades. However, the Machiavellian intelligence hypothesis, also known as the social brain hypothesis, tends to emphasize certain traits and behaviours, like exploitation and deception, at the expense of others, such as tolerance and behavioural coordination, and therefore presents only one view of how social life may shape cognition. This review outlines work from other relevant disciplines, including evolutionary economics, cognitive science and neurophysiology, to illustrate how these can be used to build a more general theoretical framework, incorporating notions of embodied and distributed cognition, in which to situate questions concerning the evolution of primate social cognition.
	Address	School of Biological Sciences, University of Liverpool, Crown Street, Liverpool L69 7ZB, UK. louiseb@liv.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:16191591			Approved	no
	Call Number				Serial	2086
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	Author	Pompilio, L.; Kacelnik, A.
	Title	State-dependent learning and suboptimal choice: when starlings prefer long over short delays to food			Type	Journal Article
	Year	2005	Publication	Animal Behaviour.	Abbreviated Journal	Anim. Behav.
	Volume	70	Issue	3	Pages	571-578
	Keywords
	Abstract	Recent studies have used labels such as `work ethics', `sunk costs' and `state-dependent preferences' for apparent anomalies in animals' choices. They suggest that preference between options relates to the options' history, rather than depending exclusively on the expected payoffs. For instance, European starlings, Sturnus vulgaris, trained to obtain identical food rewards from two sources while in two levels of hunger preferred the food source previously associated with higher hunger, regardless of the birds' state at the time of testing. We extended this experimentally and theoretically by studying starlings choosing between sources that differed not only in history but also in the objective properties (delay until reward) of the payoffs they delivered. Two options (PF and H) were initially presented in single-option sessions when subjects were, respectively, prefed or hungry. While option PF offered a delay until reward of 10 s in all treatments, option H delivered delays of 10, 12.5, 15 and 17.5 s in four treatments. When training was completed, we tested preference between the options. When delays in both options were equal (10 s), the birds strongly preferred H. When delay in H was 17.5 s, the birds were indifferent, with intermediate results for intermediate treatments. Preference was not mediated by disrupted knowledge of the delays. Thus, preferences were driven by past state-dependent gains, rather than by the joint effect of the birds' state at the time of choice and knowledge of the absolute properties of each alternative, as assumed in state-dependent, path-independent models of optimal choice.
	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
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	Area		Expedition		Conference
	Notes				Approved	no
	Call Number				Serial	2104
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	Author	Fernández-Juricic,E.; Smith, R.; Kacelnik,A.
	Title	Increasing the costs of conspecific scanning in socially foraging starlings affects vigilance and foraging behaviour			Type	Journal Article
	Year	2005	Publication	Animal Behaviour.	Abbreviated Journal	Anim. Behav.
	Volume	69	Issue	1	Pages	73-81
	Keywords
	Abstract	Social foragers receive and use information both about companions (social information) and about events external to the group, such as presence of potential predators. Scanning behaviour is often incorporated in theoretical models using simplifying assumptions in relation to the trade-off in information gathering between body postures (head-up versus head-down); however, some avian visual systems may allow individuals to scan in both body postures. We studied these issues experimentally, using starlings, Sturnus vulgaris, foraging in enclosures on natural fields. We varied the availability of information from conspecifics by placing visual barriers that blocked the view when the subjects were in head-down position and by manipulating the distance between group members. We found that as social information was reduced, starlings spent more time scanning (on and off the ground) and head-up scanning was mainly oriented towards conspecifics. The visual-obstruction effects imply that some information about conspecifics is normally gathered while starlings are foraging head-down. Neighbour distance and visual obstruction negatively affected food-searching rates and intake rates in two ways: (1) the effect of obstruction was mediated mostly through time competition between foraging and scanning on the ground, and (2) the effect of distance was due to a reduction in the rate of prey returns per searching effort while the birds were head-down. We conclude that the head-up posture is only one component of scanning, that the effects of head-down scanning should also be considered in species with ample visual fields, and that scanning in starlings is strongly connected to monitoring other flock members.
	Address
	Corporate Author				Thesis
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	Notes				Approved	no
	Call Number				Serial	2105
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	Author	Robbins, M.M.; Robbins, A.M.; Gerald-Steklis, N.; Steklis, H.D.
	Title	Long-term dominance relationships in female mountain gorillas: strength, stability and determinants of rank			Type	Journal Article
	Year	2005	Publication	Behaviour	Abbreviated Journal	Behaviour
	Volume	142	Issue	6	Pages	779-809
	Keywords
	Abstract	A common practice in studies of social animals is to rank individuals according to dominance status, which has been shown to influence access to limited resources and stability of social relationships, and may in turn correlate with reproductive success. According to the socioecological model for primates, most female dominance relationships are either nepotistic or virtually undetectable (egalitarian), with nepotistic species being philopatric, and dispersing females being egalitarian. Female mountain gorillas (Gorilla beringei beringei) disperse, and they have been characterized as being egalitarian, but previous studies have not examined their dominance relationships from a long-term perspective. We evaluated 15 matrices of displacement/supplantation interactions that spanned 30 years of observations in the Virunga Volcanoes region, and included 51 female mountain gorillas in six groups. Only 4% of displacements were directed against higher ranking females, and when matrices had less than 5% unknown dyads, linearity indices were consistently greater than 0.95. Therefore, previous results suggesting undetectable dominance relationships may have reflected an insufficient quantity of data for this species, rather than actual nonlinearity in its hierarchies. Dominance depended on age and group tenure rather than nepotism, yet some females maintained a high ranking for most of adulthood (15-25 years). Most rank shifts occurred through changes in group composition, rather than switches in established relationships. These results fit within growing evidence for linear individualistic hierarchies in some primates, often coupled with dispersal, as commonly found in ungulates. In light of these results, we propose that the dominance relationships of female mountain gorilla are best characterized as “Dispersal-Individualistic” instead of the previously suggested “Dispersal-Egalitarian”.
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	Notes				Approved	no
	Call Number	Equine Behaviour @ team @			Serial	2164
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	Author	Stevens, J.; Vervaecke, H.; de Vries, H.; Van Elsacker, L.
	Title	The influence of the steepness of dominance hierarchies on reciprocity and interchange in captive groups of bonobos (Pan paniscus)			Type	Journal Article
	Year	2005	Publication	Behaviour	Abbreviated Journal	Behaviour
	Volume	142	Issue	7	Pages	941-960
	Keywords
	Abstract	Biological market models explain variability in reciprocity and interchange between groups. In groups with a shallow dominance gradient, grooming will be mostly exchanged for itself (i.e. exchange will occur). In groups with steep dominance hierarchies, interchange is expected: individuals will groom higher ranking individuals to get access to limited resources or commodities such as support in conflicts, and grooming will be traded for these commodities. We examine patterns of reciprocity in grooming and support, and of interchange of grooming for support or for tolerance in six captive groups of bonobos. We test whether differences between groups in patterns of reciprocity and interchange can be attributed to differences in a measure of steepness of dominance hierarchies, which is based on dyadic agonistic interactions. We found that grooming was reciprocal in some, but not all groups. Support was highly reciprocal, but this was a side effect of dominance in most groups. Interchange between grooming and support was observed in some groups. Corroborating earlier findings, this was a side effect of individuals preferring high ranking individuals as grooming and support partners, possibly because these high-ranking individuals provide more efficient support in conflicts. There was no evidence for interchange of grooming for tolerance. Variability in grooming reciprocity was explained by differences in steepness of dominance hierarchies, as predicted by the biological market models. In groups with a shallow dominance hierarchy, grooming was more reciprocal. This was not true for reciprocity in support. There was some evidence that individuals groomed dominants more frequently in groups with a steep dominance hierarchy. The variation in interchange relations between grooming and support did not depend on the steepness of dominance hierarchies. We suggest that grooming in itself is a valuable commodity in bonobos, especially under captive conditions, which can be exchanged reciprocally. Bonobos may interchange grooming for another value equivalent, with food sharing as a very likely candidate. This interchange effects seem more dependent on potential to monopolise food than on steepness of dominance hierarchies per se.
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	Series Editor		Series Title		Abbreviated Series Title
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	Notes				Approved	no
	Call Number	Equine Behaviour @ team @			Serial	2194
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	Author	Christensen, J.W.; Keeling, L.J.; Nielsen, B.L.
	Title	Responses of horses to novel visual, olfactory and auditory stimuli			Type	Journal Article
	Year	2005	Publication	Applied Animal Behaviour Science	Abbreviated Journal	Appl. Anim. Behav. Sci.
	Volume	93	Issue	1-2	Pages	53-65
	Keywords	Horses; Novelty responses; Fear; Behaviour; Heart rate
	Abstract	Responses of horses towards fear-eliciting stimuli can have important consequences for both human and horse safety. This experiment was designed to investigate behavioural and heart rate (HR) responses of horses to novel visual, auditory and olfactory stimuli. Twenty-four 2-year-old, previously unhandled, stallions were habituated to receive a food reward from a container in a test arena. Each horse was exposed to three 2 min tests in a balanced design where in addition to the feed container, either a traffic cone (visual test), white noise (auditory test) or eucalyptus oil applied to the inside of the container (olfactory test) were used as the novel stimuli. Compared to the control, less time was spent eating during all tests. There was no difference in locomotion activity in the different test situations, but presentation of the novel visual and auditory stimuli elicited significantly increased HR responses in the horses, compared to their response to the arena without novel stimuli (control), whereas there was no increase in HR response to the olfactory stimulus. However, during the olfactory test, the horses had an increased number of eating bouts and became more vigilant towards their surroundings, whereas during the visual and auditory tests, more time was spent alert towards the stimulus. The horses also took significantly more steps backwards in response to the auditory test. The heart rate responses correlated between tests and reflect a non-differentiated activation of the sympathetic nervous system, while the behavioural responses were linked to the type of stimulus.
	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	2256
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