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Author Johnstone, R.A. doi  openurl
  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  
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  Language (down) 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 Viscido, S.V.; Miller, M.; Wethey, D.S. doi  openurl
  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  
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  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 Hare, B.; Call, J.; Tomasello, M. doi  openurl
  Title Do chimpanzees know what conspecifics know? Type Journal Article
  Year 2001 Publication Animal Behaviour. Abbreviated Journal Anim. Behav.  
  Volume 61 Issue 1 Pages 139-151  
  Keywords  
  Abstract We conducted three experiments on social problem solving by chimpanzees, Pan troglodytes. In each experiment a subordinate and a dominant individual competed for food, which was placed in various ways on the subordinate's side of two opaque barriers. In some conditions dominants had not seen the food hidden, or food they had seen hidden was moved elsewhere when they were not watching (whereas in control conditions they saw the food being hidden or moved). At the same time, subordinates always saw the entire baiting procedure and could monitor the visual access of their dominant competitor as well. If subordinates were sensitive to what dominants did or did not see during baiting, they should have preferentially approached and retrieved the food that dominants had not seen hidden or moved. This is what they did in experiment 1 when dominants were either uninformed or misinformed about the food's location. In experiment 2 subordinates recognized, and adjusted their behaviour accordingly, when the dominant individual who witnessed the hiding was replaced with another dominant individual who had not witnessed it, thus demonstrating their ability to keep track of precisely who has witnessed what. In experiment 3 subordinates did not choose consistently between two pieces of hidden food, one of which dominants had seen hidden and one of which they had not seen hidden. However, their failure in this experiment was likely to be due to the changed nature of the competition under these circumstances and not to a failure of social-cognitive skills. These findings suggest that at least in some situations (i.e. competition with conspecifics) chimpanzees know what conspecifics have and have not seen (do and do not know), and that they use this information to devise effective social-cognitive strategies. Copyright 2001 The Association for the Study of Animal Behaviour.  
  Address Department of Psychology and Yerkes Regional Primate Research Center, Emory University  
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  ISSN 0003-3472 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:11170704 Approved no  
  Call Number refbase @ user @ Serial 588  
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Author Peake, T.M.; Terry, A.M.; McGregor, P.K.; Dabelsteen, T. doi  openurl
  Title Male great tits eavesdrop on simulated male-to-male vocal interactions Type Journal Article
  Year 2001 Publication Proceedings. Biological sciences / The Royal Society Abbreviated Journal Proc Biol Sci  
  Volume 268 Issue 1472 Pages 1183-1187  
  Keywords Animals; Male; Songbirds/*physiology; *Vocalization, Animal  
  Abstract Animal communication generally occurs in the environment of a network of several potential signallers and receivers. Within a network environment, it is possible to gain relative information about conspecifics by eavesdropping on signalling interactions. We presented male great tits with the opportunity to gain such information by simulating singing interactions using two loudspeakers. Interactions were presented so that relevant information was not available in the absolute singing behaviour of either individual, only in the relative timing of their songs in the interaction as a whole. We then assayed the information extracted by focal males by subsequently introducing one of the 'interactants' (i.e. loudspeakers) into the territory of the focal male. Focal males responded with a reduced song output to males that had just 'lost' an interaction. Focal males did not respond significantly differently to 'winners' as compared with intruders recently involved in an interaction that contained no consistent information. Focal males also responded by switching song types more often when encountering males that had recently been involved in a low-intensity interaction. These results provide the clearest evidence yet that male songbirds extract information from signal interactions between conspecifics in the field.  
  Address Department of Animal Behaviour, Zoological Institute, Tagensvej 16, University of Copenhagen, 2200 Copenhagen N, Denmark. tmpeake@zi.ku.dk  
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  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0962-8452 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:11375107 Approved no  
  Call Number refbase @ user @ Serial 712  
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Author Stoinski, T.S.; Wrate, J.L.; Ure, N.; Whiten, A. openurl 
  Title Imitative learning by captive western lowland gorillas (Gorilla gorilla gorilla) in a simulated food-processing task Type Journal Article
  Year 2001 Publication Journal of comparative psychology (Washington, D.C. : 1983) Abbreviated Journal J Comp Psychol  
  Volume 115 Issue 3 Pages 272-281  
  Keywords Animals; Behavior, Animal/physiology; *Discrimination Learning; Feeding Behavior/*physiology; Gorilla gorilla; *Imitative Behavior; Social Behavior  
  Abstract Although field studies have suggested the existence of cultural transmission of foraging techniques in primates, identification of transmission mechanisms has remained elusive. To test experimentally for evidence of imitation in the current study, we exposed gorillas (Gorilla gorilla gorilla) to an artificial fruit foraging task designed by A. Whiten and D. M. Custance (1996). Gorillas (n=6) watched a human model remove a series of 3 defenses around a fruit. Each of the defenses was removed using 1 of 2 alternative techniques. Subsequent video analysis of gorillas' behavior showed a significant tendency to copy the observed technique on 1 of the individual defenses and the direction of removal on another defense. This is the first statistically reliable evidence of imitation in gorillas. Sequence of defense removal was not replicated. The gorillas' responses were most similar to those of chimpanzees.  
  Address TECHlab, Zoo Atlanta, Georgia 30315, USA. stoinskit@mindspring.com  
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  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0735-7036 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:11594496 Approved no  
  Call Number refbase @ user @ Serial 738  
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Author Whiten, A.; McGrew, W.C. doi  openurl
  Title Is this the first portrayal of tool use by a chimp? Type
  Year 2001 Publication Nature Abbreviated Journal Nature  
  Volume 409 Issue 6816 Pages 12  
  Keywords Animals; *Behavior, Animal; Pan troglodytes/*physiology; Philately  
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  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0028-0836 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:11343083 Approved no  
  Call Number refbase @ user @ Serial 739  
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Author Whiten, A.; Boesch, C. openurl 
  Title The cultures of chimpanzees Type Journal Article
  Year 2001 Publication Scientific American Abbreviated Journal Sci Am  
  Volume 284 Issue 1 Pages 60-67  
  Keywords Animals; *Behavior, Animal; Culture; Feeding Behavior; Grooming; Hominidae; Humans; Pan troglodytes/*physiology  
  Abstract  
  Address University of St. Andrews  
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  Series Volume Series Issue Edition  
  ISSN 0036-8733 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:11132425 Approved no  
  Call Number refbase @ user @ Serial 740  
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Author Jansen, W.L.; van Alphen, M.; Berghout, M.; Everts, H.; Beynen, A.C. url  doi
openurl 
  Title An approach to assessment of the efficiency of dietary energy utilization by horses and ponies kept at riding schools Type Journal Article
  Year 2001 Publication The Veterinary quarterly Abbreviated Journal Vet Q  
  Volume 23 Issue 4 Pages 195-198  
  Keywords *Animal Feed; Animal Husbandry; Animals; Body Weight; Dietary Fats; Dietary Fiber; *Energy Intake; *Energy Metabolism; Female; Horses/*physiology; Male  
  Abstract The ratio of calculated net energy intake (NEi) to calculate net energy requirement (NEr) might serve as an indicator of the efficiency of dietary energy utilization. The ratio was determined for 93 horses and ponies from 10 riding schools. For each animal with an assumed constant body weight, energy intake and energy requirements were assessed. On average, the estimated NEi was 14% greater than NEr. There was a significant, negative association between crude fibre intake and the NEi: NEr ratio. Earlier work indicated that extra fat intake may lead to over estimation of the calculated energy value of the ration due to changes in macronutrient digestibility. Dietary fat concentration was found to range from 32 to 52 g/kg dry matter (5 to 6 g/MJ net energy), but on the basis of digestibility trials this range in fat concentration is too small to significantly influence the NEi: NEr ratio. This study shows that assessment of the efficiency of dietary energy utilization under normal conditions, on the basis of the NEi: NEr ratio is fraught with uncertainty.  
  Address Department of Nutrition, Faculty of Veterinary, Medicine, Utrecht University, The Netherlands  
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  Series Volume Series Issue Edition  
  ISSN 0165-2176 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:11765239 Approved no  
  Call Number Serial 1807  
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Author Miller, R.M. openurl 
  Title Behavior and misbehavior of the horse Type Journal Article
  Year 2001 Publication The Veterinary Clinics of North America. Equine Practice Abbreviated Journal Vet Clin North Am Equine Pract  
  Volume 17 Issue 2 Pages 379-87, ix  
  Keywords Animals; Behavior, Animal/*physiology; Curriculum; Education, Veterinary; Horses/*physiology/*psychology; United States  
  Abstract For decades after the discipline of psychiatry had been established as an accepted specialty, many medical schools continued to fail to train their students in the fundamentals of this discipline. Medical students all have at least cursory exposure to psychiatric principles and basic psychology. Unfortunately, the veterinary profession has lagged behind human medicine in this regard. Until recently, veterinary students received no training in animal behavior, and there were no available residencies within our schools for developing board-certified behavioral specialists.  
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  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0749-0739 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:15658182 Approved no  
  Call Number Serial 1894  
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Author Budras, K.D.; Scheibe, K.; Patan, B.; Streich, W.J.; Kim, K. openurl 
  Title Laminitis in Przewalski horses kept in a semireserve Type Journal Article
  Year 2001 Publication Journal of Veterinary Science (Suwon-si, Korea) Abbreviated Journal J Vet Sci  
  Volume 2 Issue 1 Pages 1-7  
  Keywords Animals; Animals, Domestic; Animals, Wild; Body Weight; Climate; Geography; Horse Diseases/*epidemiology; Horses; Korea/epidemiology; Lameness, Animal/*epidemiology  
  Abstract Semireserves were created by the European Conservation Project for scientific research in preparation for reintroduction in the wilderness. They are defined as enclosures large enough to carry a group of Przewalski horses throughout the year without any additional feeding. The semireserve offers diverse opportunities for significant scientific research. As part of a general screening program, the hoof development in a group of Przewalski horses was investigated in the semireserve Schorfheide near Berlin. Since the foundation of this semireserve in 1992, veterinary treatment was not necessary with the exception of hoof trimming in two animals in 1993. However, major health problems were encountered in the spring of 1999, when three other mares showed signs of laminitis. The initial diagnosis by the authors and the local veterinary surgeon based on observation of behaviour, gait, stance, walk and trot of three mares whose initial weights were higher than those of the healthy mares. The initial diagnosis was confirmed by palpation and the occurrence of very deep horn rings on all hooves and a laminitic horn ring on the right front hoof of one mare. An adequate laminitic therapy was not possible under the conditions of a semireserve. The applied management aimed at two goals: 1. To reduce endotoxin production and acidosis in the horses by reducing the ingestion of carbohydrate rich food. 2. To reduce the mares level of activity and to prevent tearing of the suspensory apparatus of the coffin bone. To achieve these two goals it was decided to remove the three laminitic mares from the rich pasture in the main part of the semireserve and to confine them onto the poorer pasture of the small separately fenced area. All three affected mares had fully recovered from their laminitic condition. Prevention of grass laminitis can be achieved by the following measures: 1. Reduction in grass intake could be achieved by increasing the grazing pressure by an increase in stocking rate of the horses or mixed grazing with another species such as sheep. 2. A longer term solution to the problem may well be to sow specific varieties of grass with lower concentrations of water soluble carbohydrate.  
  Address Institute of Veterinary Anatomy of the Free University of Berlin, Berlin 33, Germany. budras@vetmed.fu-berlin.de  
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  Series Volume Series Issue Edition  
  ISSN 1229-845X ISBN Medium  
  Area Expedition Conference  
  Notes PMID:14614287 Approved no  
  Call Number Serial 1905  
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