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	Author	Bergstrom, C.T.; Lachmann, M.
	Title	Signaling among relatives. III. Talk is cheap			Type	Journal Article
	Year	1998	Publication	Proceedings of the National Academy of Sciences of the United States of America	Abbreviated Journal	Proc. Natl. Acad. Sci. U.S.A.
	Volume	95	Issue	9	Pages	5100-5105
	Keywords	Animal Communication; Animals; Costs and Cost Analysis; *Evolution; Interpersonal Relations; Models, Biological
	Abstract	The Sir Philip Sidney game has been used by numerous authors to show how signal cost can facilitate honest signaling among relatives. Here, we demonstrate that, in this game, honest cost-free signals are possible as well, under very general conditions. Moreover, these cost-free signals are better for all participants than the previously explored alternatives. Recent empirical evidence suggests that begging is energetically inexpensive for nestling birds; this finding led some researchers to question the applicability of the costly signaling framework to nestling begging. Our results show that cost-free or inexpensive signals, as observed empirically, fall within the framework of signaling theory.
	Address	Department of Biological Sciences, Stanford University, Stanford, CA 94305, USA. carl@charles.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	0027-8424	ISBN		Medium
	Area		Expedition		Conference
	Notes	PMID:9560235			Approved	no
	Call Number	refbase @ user @			Serial	561
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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	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	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	Uehara, T.; Yokomizo, H.; Iwasa, Y.
	Title	Mate-choice copying as Bayesian decision making			Type	Journal Article
	Year	2005	Publication	The American naturalist	Abbreviated Journal	Am Nat
	Volume	165	Issue	3	Pages	403-410
	Keywords	Animals; Bayes Theorem; Choice Behavior; Female; Male; Models, Biological; Sexual Behavior, Animal
	Abstract	Mate-choice copying by females has been reported in fishes (e.g., guppies) and lekking birds. Presumably, females assess males' quality using both information from direct observation of males and information acquired by observing other females' choices. Here, we study mathematically the conditions under which mate-choice copying is advantageous on the basis of Bayesian decision theory. A female may observe the mate choice of another female, called the model female, who has performed an optimal choice based on her own judgment. The conditions required for the focal female to choose the same mate as that chosen by the model female should depend on the male's appearance to her, the reliability of her own judgment of male quality, and the reliability of the model females. When three or more females are involved, the optimal mate choice critically depends on whether multiple model females make decisions independently or they themselves copy the choices of others. If two equally reliable females choose different males, the choice of the second female, made knowing the choice of the first, should have a stronger effect on the choice of the third (focal) female. This “last-choice precedence” should be tested experimentally.
	Address	Department of Biology, Faculty of Sciences, Kyushu University, Fukuoka 812-8581, Japan. uehara@bio-math.biology.kyushu-u.ac.jp
	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:15729669			Approved	no
	Call Number				Serial	1821
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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	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	Waite, T.A.
	Title	Interruptions improve choice performance in gray jays: prolonged information processing versus minimization of costly errors			Type	Journal Article
	Year	2002	Publication	Animal Cognition	Abbreviated Journal	Anim. Cogn.
	Volume	5	Issue	4	Pages	209-214
	Keywords	Animals; Behavior, Animal; Choice Behavior; Female; Learning; Male; Models, Biological; Motivation; Reinforcement Schedule; Songbirds/*physiology; Time Factors
	Abstract	Under the assumption that selection favors minimization of costly errors, erroneous choice may be common when its fitness cost is low. According to an adaptive-choice model, this cost depends on the rate at which an animal encounters the choice: the higher this rate, the smaller the cost of choosing a less valuable option. Errors should thus be more common when interruptions to foraging are shorter. A previous experiment supported this prediction: gray jays, Perisoreus canadensis, were more error prone when subjected to shorter delays to access to food rewards. This pattern, though, is also predicted by an attentional-constraints model. Because the subjects were able to inspect the rewards during delays, their improved performance when subjected to longer delays could have been a byproduct of the experimentally prolonged opportunity for information processing. To evaluate this possibility, a follow-up experiment manipulated both delay to access and whether rewards could be inspected during delays. Depriving jays of the opportunity to inspect rewards (using opaque lids) induced only a small, nonsignificant increase in error rate. This effect was independent of length of delay and so the jays' improved performance when subjected to longer delays was not simply a byproduct of prolonged information processing. More definitively, even when the jays were prevented from inspecting rewards during delays, their performance improved when subjected to longer delays. The findings are thus consistent with the adaptive-choice model.
	Address	Department of Evolution, Ecology, and Organismal Biology, Ohio State University, 1735 Neil Avenue, Columbus, OH 43210-1293, USA. waite.1@osu.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	1435-9448	ISBN		Medium
	Area		Expedition		Conference
	Notes	PMID:12461598			Approved	no
	Call Number	Equine Behaviour @ team @			Serial	2592
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	Author	Izar, P.; Ferreira, R.G.; Sato, T.
	Title	Describing the organization of dominance relationships by dominance-directed tree method			Type	Journal Article
	Year	2006	Publication	American journal of primatology	Abbreviated Journal	Am. J. Primatol.
	Volume	68	Issue	2	Pages	189-207
	Keywords	Animals; Cebus/physiology; Models, Biological; Social Dominance
	Abstract	Methods to describe dominance hierarchies are a key tool in primatology studies. Most current methods are appropriate for analyzing linear and near-linear hierarchies; however, more complex structures are common in primate groups. We propose a method termed “dominance-directed tree.” This method is based on graph theory and set theory to analyze dominance relationships in social groups. The method constructs a transitive matrix by imposing transitivity to the dominance matrix and produces a graphical representation of the dominance relationships, which allows an easy visualization of the hierarchical position of the individuals, or subsets of individuals. The method is also able to detect partial and complete hierarchies, and to describe situations in which hierarchical and nonhierarchical principles operate. To illustrate the method, we apply a dominance tree analysis to artificial data and empirical data from a group of Cebus apella.
	Address	Department of Experimental Psychology, University of Sao Paulo, Brazil. patrizar@usp.br
	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	0275-2565	ISBN		Medium
	Area		Expedition		Conference
	Notes	PMID:16429416			Approved	no
	Call Number	refbase @ user @			Serial	723
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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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