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	Author	Johnstone, R.A.
	Title	Eavesdropping and animal conflict			Type	Journal Article
	Year	2001	Publication	Proceedings of the National Academy of Sciences of the United States of America	Abbreviated Journal	Proc. Natl. Acad. Sci. U.S.A.
	Volume	98	Issue	16	Pages	9177-9180
	Keywords	Aggression; Animals; Behavior, Animal; *Conflict (Psychology); Models, Theoretical
	Abstract	Fights between pairs of animals frequently take place within a wider social context. The displays exchanged during conflict, and the outcome of an encounter, are often detectable by individuals who are not immediately involved. In at least some species, such bystanders are known to eavesdrop on contests between others, and to modify their behavior toward the contestants in response to the observed interaction. Here, I extend Maynard Smith's well known model of animal aggression, the Hawk-Dove game, to incorporate the possibility of eavesdroppers. I show that some eavesdropping is favored whenever the cost of losing an escalated fight exceeds the value of the contested resource, and that its equilibrium frequency is greatest when costs are relatively high. Eavesdropping reduces the risk of escalated conflict relative to that expected by chance, given the level of aggression in the population. However, it also promotes increased aggression, because it enhances the value of victory. The net result is that escalated conflicts are predicted to occur more frequently when eavesdropping is possible.
	Address	Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, United Kingdom. raj1003@hermes.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	0027-8424	ISBN		Medium
	Area		Expedition		Conference
	Notes	PMID:11459936			Approved	no
	Call Number	refbase @ user @			Serial	497
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	Author	Clutton-Brock, T.H.; Russell, A.F.; Sharpe, L.L.; Brotherton, P.N.; McIlrath, G.M.; White, S.; Cameron, E.Z.
	Title	Effects of helpers on juvenile development and survival in meerkats			Type	Journal Article
	Year	2001	Publication	Science (New York, N.Y.)	Abbreviated Journal	Science
	Volume	293	Issue	5539	Pages	2446-2449
	Keywords	Animals; Breeding; Carnivora/growth & development/physiology; Cooperative Behavior; Feeding Behavior; Female; Male; Survival Rate; *Weight Gain
	Abstract	Although breeding success is known to increase with group size in several cooperative mammals, the mechanisms underlying these relationships are uncertain. We show that in wild groups of cooperative meerkats, Suricata suricatta, reductions in the ratio of helpers to pups depress the daily weight gain and growth of pups and the daily weight gain of helpers. Increases in the daily weight gain of pups are associated with heavier weights at independence and at 1 year of age, as well as with improved foraging success as juveniles and higher survival rates through the first year of life. These results suggest that the effects of helpers on the fitness of pups extend beyond weaning and that helpers may gain direct as well as indirect benefits by feeding pups.
	Address	Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK. thcb@hermes.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	0036-8075	ISBN		Medium
	Area		Expedition		Conference
	Notes	PMID:11577235			Approved	no
	Call Number	refbase @ user @			Serial	414
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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	Meershoek, L.S.; Schamhardt, H.C.; Roepstorff, L.; Johnston, C.
	Title	Forelimb tendon loading during jump landings and the influence of fence height			Type	Journal Article
	Year	2001	Publication	Equine Veterinary Journal. Supplement	Abbreviated Journal	Equine Vet J Suppl
	Volume		Issue	33	Pages	6-10
	Keywords	Animals; Biomechanics; Forelimb/injuries/physiology; Horses/injuries/physiology; Lameness, Animal/etiology; Ligaments, Articular/physiology; Locomotion/physiology; Physical Conditioning, Animal; Tendon Injuries/complications/physiopathology/veterinary; Tendons/physiology; Weight-Bearing/physiology
	Abstract	Lameness in athletic horses is often caused by forelimb tendon injuries, especially in the interosseus tendon (TI) and superficial digital flexor tendon (SDF), but also in the accessory ligament (AL) of the deep digital flexor tendon (DDF). In an attempt to explain the aetiology of these injuries, the present study investigated the loading of the tendons during landing after a jump. In jumping horses, the highest forces can be expected in the trailing limb during landing. Therefore, landing kinematics and ground reaction forces of the trailing forelimb were measured from 6 horses jumping single fences with low to medium heights of 0.80, 1.00 and 1.20 m. The tendon forces were calculated using inverse dynamics and an in vitro model of the lower forelimb. Calculated peak forces in the TI, SDF and DDF + AL during landing were 15.8, 13.9 and 11.7 kN respectively. The relative loading of the tendons (landing forces compared with failure forces determined in a separate study) increased from DDF to TI to SDF and was very high in SDF. This explains the low injury incidence of the DDF and the high injury incidence of the SDF. Fence height substantially influenced SDF forces, whereas it hardly influenced TI forces and did not influence AL strain. Reduction of fence height might therefore limit the risks for SDF injuries, but not for TI and AL injuries.
	Address	Department of Veterinary Anatomy and Physiology, Institute for Fundamental and Clinical Human Movement Sciences, Faculty of Veterinary Medicine, Utrecht University, 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		ISBN		Medium
	Area		Expedition		Conference
	Notes	PMID:11721571			Approved	no
	Call Number	Equine Behaviour @ team @			Serial	3786
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	Author	Meershoek, L.S.; Roepstorff, L.; Schamhardt, H.C.; Johnston, C.; Bobbert, M.F.
	Title	Joint moments in the distal forelimbs of jumping horses during landing			Type	Journal Article
	Year	2001	Publication	Equine Veterinary Journal	Abbreviated Journal	Equine Vet J
	Volume	33	Issue	4	Pages	410-415
	Keywords	Animals; Biomechanics; Forelimb/physiology; Gait/physiology; Horses/physiology; Joints/physiology; Physical Conditioning, Animal; Tendons/physiology; Weight-Bearing
	Abstract	Tendon injuries are an important problem in athletic horses and are probably caused by excessive loading of the tendons during demanding activities. As a first step towards understanding these injuries, the tendon loading was quantified during jump landings. Kinematics and ground reaction forces were collected from the leading and trailing forelimbs of 6 experienced jumping horses. Joint moments were calculated using inverse dynamic analysis. It was found that the variation of movement and loading patterns was small, both within and between horses. The peak flexor joint moments in the coffin and fetlock joints were larger in the trailing limb (-0.62 and -2.44 Nm/kg bwt, respectively) than in the leading limb (-0.44 and -1.93 Nm/kg bwt, respectively) and exceeded literature values for trot by 82 and 45%. Additionally, there was an extensor coffin joint moment in the first half of the stance phase of the leading limb (peak value 0.26+/-0.18 Nm/kg bwt). From these results, it was concluded that the loading of the flexor tendons during landing was higher in the trailing than in the leading limb and that there was an unexpected loading of the extensor tendon in the leading limb.
	Address	Department of Veterinary Anatomy and Physiology, Faculty of Veterinary Medicine, Utrecht University, 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	0425-1644	ISBN		Medium
	Area		Expedition		Conference
	Notes	PMID:11469776			Approved	no
	Call Number	Equine Behaviour @ team @			Serial	3787
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	Author	Bouchard, T.J.J.; Loehlin, J.C.
	Title	Genes, evolution, and personality			Type	Journal Article
	Year	2001	Publication	Behavior Genetics	Abbreviated Journal	Behav Genet
	Volume	31	Issue	3	Pages	243-273
	Keywords	Animals; Evolution; Genetics, Behavioral; Humans; Individuality; Personality/genetics; Twin Studies
	Abstract	There is abundant evidence, some of it reviewed in this paper, that personality traits are substantially influenced by the genes. Much remains to be understood about how and why this is the case. We argue that placing the behavior genetics of personality in the context of epidemiology, evolutionary psychology, and neighboring psychological domains such as interests and attitudes should help lead to new insights. We suggest that important methodological advances, such as measuring traits from multiple viewpoints, using large samples, and analyzing data by modern multivariate techniques, have already led to major changes in our view of such perennial puzzles as the role of “unshared environment” in personality. In the long run, but not yet, approaches via molecular genetics and brain physiology may also make decisive contributions to understanding the heritability of personality traits. We conclude that the behavior genetics of personality is alive and flourishing but that there remains ample scope for new growth and that much social science research is seriously compromised if it does not incorporate genetic variation in its explanatory models.
	Address	Department of Psychology. University of Minnesota, Minneapolis 55455, USA. bouch001@tc.umn.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	0001-8244	ISBN		Medium
	Area		Expedition		Conference
	Notes	PMID:11699599			Approved	no
	Call Number	Equine Behaviour @ team @			Serial	4142
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	Author	Gibson, B.M.; Shettleworth, S.J.; McDonald, R.J.
	Title	Finding a goal on dry land and in the water: differential effects of disorientation on spatial learning			Type	Journal Article
	Year	2001	Publication	Behavioural brain research	Abbreviated Journal	Behav. Brain. Res.
	Volume	123	Issue	1	Pages	103-111
	Keywords	Animals; Cues; Environment; Male; Maze Learning/physiology; Orientation/physiology; Rats; Rats, Long-Evans; Spatial Behavior/*physiology; Water
	Abstract	Two previous studies, Martin et al. (J. Exp. Psychol. Anim. Behav. Process. 23 (1997) 183) and Dudchenko et al. (J. Exp. Psychol. Anim. Behav. Process. 23 (1997) 194), report that, compared to non-disoriented controls, rats disoriented before testing were disrupted in their ability to learn the location of a goal on a dry radial-arm maze task, but that both groups learned at the same rate in the Morris water maze. However, the radial-arm maze task was much more difficult than the water maze. In the current set of experiments, we examined the performance of control and disoriented rats on more comparable dry land and water maze tasks. Compared to non-disoriented rats, rats that were disoriented before testing were significantly impaired in locating a goal in a circular dry arena, but not a water tank. The results constrain theoretical explanations for the differential effects of disorientation on different spatial tasks.
	Address	Department of Psychology, University of Toronto, 100 St. George Street, Toronto, Ontario, Canada M5S 3G3. gibson@psych.utoronto.ca
	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	0166-4328	ISBN		Medium
	Area		Expedition		Conference
	Notes	PMID:11377733			Approved	no
	Call Number	refbase @ user @			Serial	372
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	Author	Zentall, T.R.; Clement, T.S.; Bhatt, R.S.; Allen, J.
	Title	Episodic-like memory in pigeons			Type	Journal Article
	Year	2001	Publication	Psychonomic bulletin & review	Abbreviated Journal	Psychon Bull Rev
	Volume	8	Issue	4	Pages	685-690
	Keywords	Animals; Behavior, Animal/physiology; Columbidae; Memory, Short-Term/*physiology; Teaching
	Abstract	It has been proposed that memory for personal experiences (episodic memory, rather than semantic memory) relies on the conscious review of past experience and thus is unique to humans. In an attempt to demonstrate episodic-like memory in animals, we first trained pigeons to respond to the (nonverbal) question “Did you just peck or did you just refrain from pecking?” by training them on a symbolic matching task with differential responding required to the two line-orientation samples and reinforcing the choice of a red comparison if they had pecked and the choice of a green comparison if they had not pecked. Then, in Experiment 1, after providing the conditions for (but not requiring) the pigeons to peck at one new stimulus (a yellow hue) but not at another (a blue hue), we tested them with the new hue stimuli and the red and green comparisons. In Experiment 2, we tested the pigeons with novel stimuli (a circle, which they spontaneously pecked, and a dark response key, which they did not peck) and the red and green comparisons. In both experiments, pigeons chose the comparison appropriate to the response made to the test stimulus. Thus, the pigeons demonstrated that they could remember specific details about their past experiences, a result consistent with the notion that they have the capacity for forming episodic-like memories.
	Address	Department of Psychology, University of Kentucky, Lexington 40506-0044, USA. zentall@pop.uky.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	1069-9384	ISBN		Medium
	Area		Expedition		Conference
	Notes	PMID:11848586			Approved	no
	Call Number	refbase @ user @			Serial	243
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	Author	Dorrance, B.R.; Zentall, T.R.
	Title	Imitative learning in Japanese quail (Coturnix japonica) depends on the motivational state of the observer quail at the time of observation			Type	Journal Article
	Year	2001	Publication	Journal of comparative psychology (Washington, D.C. : 1983)	Abbreviated Journal	J Comp Psychol
	Volume	115	Issue	1	Pages	62-67
	Keywords	Animals; Behavior, Animal; Coturnix; Female; Imitative Behavior; Learning; Male; *Motivation; Reinforcement (Psychology); Time Factors
	Abstract	The 2-action method was used to examine whether imitative learning in Japanese quail (Coturnix japonica) depends on the motivational state of the observer quail at the time of observation of the demonstrated behavior. Two groups of observers were fed before observation (satiated groups), whereas 2 other groups of observers were deprived of food before observation (hungry groups). Quail were tested either immediately following observation or after a 30-min delay. Results indicated that quail in the hungry groups imitated, whereas those in the satiated groups did not, regardless of whether their test was immediate or delayed. The results suggest that observer quail may not learn (through observation) behavior that leads to a reinforcer for which they are unmotivated at the time of test. In addition, the results show that quail are able to delay the performance of a response acquired through observation (i.e., they show deferred imitation).
	Address	Department of Psychology, University of Kentucky, Lexington 40506-0044, USA
	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	0735-7036	ISBN		Medium
	Area		Expedition		Conference
	Notes	PMID:11334220			Approved	no
	Call Number	refbase @ user @			Serial	245
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	Author	Zentall, T.R.
	Title	The case for a cognitive approach to animal learning and behavior			Type	Journal Article
	Year	2001	Publication	Behavioral Processes	Abbreviated Journal	Behav Processes
	Volume	54	Issue	1-3	Pages	65-78
	Keywords
	Abstract	The dangers of hypothesizing about unobservable cognitive mechanisms are well known to behavior analysts. I propose, however, that carefully fashioned cognitive theories that make predictions that are inconsistent with current behavioral theories can provide useful research tools for the understanding of behavior. Furthermore, even if the results of such research may be accommodated by modifying existing behavioral theories, our understanding of behavior is often advanced by the empirical findings because it is unlikely that the research would have been conducted in the absence of such cognitive hypothesizing. Two examples of the development of emergent relations are described: The first deals with the nature of a pigeon's 'representation' of two stimuli both of which are associated with correct responding to a third in a many-to-one matching task (stimulus equivalence or common representations). The second has to do with transitive inference, the emergent relation between two stimuli mediated by their relation to a common stimulus in a simultaneous discrimination.
	Address	Department of Psychology, University of Kentucky, 40506-0044, Lexington, KY, USA
	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	0376-6357	ISBN		Medium
	Area		Expedition		Conference
	Notes	PMID:11369461			Approved	no
	Call Number				Serial	25
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