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	Author	Wilson, A.M.; McGuigan, M.P.; Su, A.; van Den Bogert, A.J.
	Title	Horses damp the spring in their step			Type	Journal Article
	Year	2001	Publication	Nature	Abbreviated Journal	Nature
	Volume	414	Issue	6866	Pages	895-899
	Keywords	Animals; Biomechanics; Elasticity; Forelimb; Gait; Horses/anatomy & histology/physiology; Leg Bones/physiology; Locomotion; Models, Biological; Muscle Fibers/physiology; Muscle, Skeletal/anatomy & histology/physiology; Tendons/anatomy & histology/physiology; Vibration
	Abstract	The muscular work of galloping in horses is halved by storing and returning elastic strain energy in spring-like muscle-tendon units.These make the legs act like a child's pogo stick that is tuned to stretch and recoil at 2.5 strides per second. This mechanism is optimized by unique musculoskeletal adaptations: the digital flexor muscles have extremely short fibres and significant passive properties, whereas the tendons are very long and span several joints. Length change occurs by a stretching of the spring-like digital flexor tendons rather than through energetically expensive length changes in the muscle. Despite being apparently redundant for such a mechanism, the muscle fibres in the digital flexors are well developed. Here we show that the mechanical arrangement of the elastic leg permits it to vibrate at a higher frequency of 30-40 Hz that could cause fatigue damage to tendon and bone. Furthermore, we show that the digital flexor muscles have minimal ability to contribute to or regulate significantly the 2.5-Hz cycle of movement, but are ideally arranged to damp these high-frequency oscillations in the limb.
	Address	Department of Veterinary Basic Sciences, The Royal Veterinary College, Hatfield, Herts AL9 7TA, UK. awilson@rvc.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:11780059			Approved	no
	Call Number	Equine Behaviour @ team @			Serial	2300
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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
Permanent link to this record



	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	Kiltie, R.A.; Fan, J.; Laine, A.F.
	Title	A wavelet-based metric for visual texture discrimination with applications in evolutionary ecology			Type	Journal Article
	Year	1995	Publication	Mathematical Biosciences	Abbreviated Journal	Math Biosci
	Volume	126	Issue	1	Pages	21-39
	Keywords	Animals; Carnivora; Ecology; Equidae; Evolution; Humans; Mathematics; Models, Biological; Moths; *Pattern Recognition, Visual; Pigmentation
	Abstract	Much work on natural and sexual selection is concerned with the conspicuousness of visual patterns (textures) on animal and plant surfaces. Previous attempts by evolutionary biologists to quantify apparency of such textures have involved subjective estimates of conspicuousness or statistical analyses based on transect samples. We present a method based on wavelet analysis that avoids subjectivity and that uses more of the information in image textures than transects do. Like the human visual system for texture discrimination, and probably like that of other vertebrates, this method is based on localized analysis of orientation and frequency components of the patterns composing visual textures. As examples of the metric's utility, we present analyses of crypsis for tigers, zebras, and peppered moth morphs.
	Address	Department of Zoology, University of Florida, Gainesville
	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	0025-5564	ISBN		Medium
	Area		Expedition		Conference
	Notes	PMID:7696817			Approved	no
	Call Number	Equine Behaviour @ team @			Serial	2660
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	Author	Viscido, S.V.; Miller, M.; Wethey, D.S.
	Title	The dilemma of the selfish herd: the search for a realistic movement rule			Type	Journal Article
	Year	2002	Publication	Journal of theoretical biology	Abbreviated Journal	J. Theor. Biol.
	Volume	217	Issue	2	Pages	183-194
	Keywords	Animals; Behavior, Animal; Mass Behavior; Models, Biological; *Motor Activity; Predatory Behavior
	Abstract	The selfish herd hypothesis predicts that aggregations form because individuals move toward one another to minimize their own predation risk. The “dilemma of the selfish herd” is that movement rules that are easy for individuals to follow, fail to produce true aggregations, while rules that produce aggregations require individual behavior so complex that one may doubt most animals can follow them. If natural selection at the individual level is responsible for herding behavior, a solution to the dilemma must exist. Using computer simulations, we examined four different movement rules. Relative predation risk was different for all four movement rules (p<0.05). We defined three criteria for measuring the quality of a movement rule. A good movement rule should (a) be statistically likely to benefit an individual that follows it, (b) be something we can imagine most animals are capable of following, and (c) result in a centrally compact flock. The local crowded horizon rule, which allowed individuals to take the positions of many flock-mates into account, but decreased the influence of flock-mates with distance, best satisfied these criteria. The local crowded horizon rule was very sensitive to the animal's perceptive ability. Therefore, the animal's ability to detect its neighbors is an important factor in the dynamics of group formation.
	Address	Department of Biological Sciences, University of South Carolina, Columbia, SC, 29208, USA. viscido@u.washington.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	0022-5193	ISBN		Medium
	Area		Expedition		Conference
	Notes	PMID:12202112			Approved	no
	Call Number	refbase @ user @			Serial	554
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	Author	Viscido, S.V.; Miller, M.; Wethey, D.S.
	Title	The response of a selfish herd to an attack from outside the group perimeter			Type	Journal Article
	Year	2001	Publication	Journal of theoretical biology	Abbreviated Journal	J. Theor. Biol.
	Volume	208	Issue	3	Pages	315-328
	Keywords	Animals; Behavior, Animal; Computer Simulation; Models, Biological; *Movement; Predatory Behavior
	Abstract	According to the selfish herd hypothesis, animals can decrease predation risk by moving toward one another if the predator can appear anywhere and will attack the nearest target. Previous studies have shown that aggregations can form using simple movement rules designed to decrease each animal's Domain of Danger. However, if the predator attacks from outside the group's perimeter, these simple movement rules might not lead to aggregation. To test whether simple selfish movement rules would decrease predation risk for those situations when the predator attacks from outside the flock perimeter, we constructed a computer model that allowed flocks of 75 simulated fiddler crabs to react to one another, and to a predator attacking from 7 m away. We attacked simulated crab flocks with predators of different sizes and attack speeds, and computed relative predation risk after 120 time steps. Final trajectories showed flight toward the center of the flock, but curving away from the predator. Path curvature depended on the predator's size and approach speed. The average crab experienced a greater decrease in predation risk when the predator was small or slow moving. Regardless of the predator's size and speed, however, predation risk always decreased as long as crabs took their flock-mates into account. We conclude that, even when flight away from an external predator occurs, the selfish avoidance of danger can lead to aggregation.
	Address	Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, U.S.A. viscido@u.washington.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	0022-5193	ISBN		Medium
	Area		Expedition		Conference
	Notes	PMID:11207093			Approved	no
	Call Number	refbase @ user @			Serial	555
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	Author	Hamilton, W.D.
	Title	Geometry for the selfish herd			Type	Journal Article
	Year	1971	Publication	Journal of theoretical biology	Abbreviated Journal	J. Theor. Biol.
	Volume	31	Issue	2	Pages	295-311
	Keywords	Animals; Anura; Behavior, Animal; Breeding; Communication; Evolution; Fear; Metallurgy; Models, Biological; Probability; Snakes; *Spatial Behavior
	Abstract	This paper presents an antithesis to the view that gregarious behaviour is evolved through benefits to the population or species. Following Galton (1871) and Williams (1964) gregarious behaviour is considered as a form of cover-seeking in which each animal tries to reduce its chance of being caught by a predator. It is easy to see how pruning of marginal individuals can maintain centripetal instincts in already gregarious species; some evidence that marginal pruning actually occurs is summarized. Besides this, simply defined models are used to show that even in non-gregarious species selection is likely to favour individuals who stay close to others. Although not universal or unipotent, cover-seeking is a widespread and important element in animal aggregation, as the literature shows. Neglect of the idea has probably followed from a general disbelief that evolution can be dysgenic for a species. Nevertheless, selection theory provides no support for such disbelief in the case of species with outbreeding or unsubdivided populations. The model for two dimensions involves a complex problem in geometrical probability which has relevance also in metallurgy and communication science. Some empirical data on this, gathered from random number plots, is presented as of possible heuristic value.
	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	0022-5193	ISBN		Medium
	Area		Expedition		Conference
	Notes	PMID:5104951			Approved	no
	Call Number	refbase @ user @			Serial	771
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	Author	Seyfarth, R.M.
	Title	A model of social grooming among adult female monkeys			Type	Journal Article
	Year	1977	Publication	Journal of Theoretical Biology	Abbreviated Journal	J. Theor. Biol.
	Volume	65	Issue	4	Pages	671-698
	Keywords	Animals; Behavior, Animal; Female; Grooming; Haplorhini/physiology; *Models, Biological; Reproduction; Social Dominance; Time Factors
	Abstract	Grooming networks among adult female monkeys exhibit two similar features across a number of different species. High-ranking animals receive more grooming than others, and the majority of grooming occurs between females of adjacent rank. A theoretical model which duplicates these features is presented, and the properties of the model are used to explain the possible causation and function of female grooming behaviour. The model illustrates how relatively simple principles governing the behaviour of individuals may be used to explain more complex aspects of the social structure of non-human primate groups.
	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	0022-5193	ISBN		Medium
	Area		Expedition		Conference
	Notes	PMID:406485			Approved	no
	Call Number	Equine Behaviour @ team @			Serial	5259
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