Records |
Author |
Hernandez, J.; Hawkins, D.L. |
Title |
Training failure among yearling horses |
Type |
Journal Article |
Year |
2001 |
Publication |
American Journal of Veterinary Research |
Abbreviated Journal |
Am J Vet Res |
Volume |
62 |
Issue |
9 |
Pages |
1418-1422 |
Keywords |
Animals; Female; Florida; Horses/*physiology; Lameness, Animal/*economics; Male; Physical Conditioning, Animal/adverse effects/economics; Respiratory Tract Diseases/economics/*veterinary; Statistics, Nonparametric |
Abstract |
OBJECTIVE: To compare financial returns between pinhooked yearling horses (ie, bought and trained for approximately 5 months with the goal of selling the horse at “2-year-olds in training” sales) that had mild or severe training failure and horses that had planned versus nonplanned training failure. ANIMALS: 40 Thoroughbred pinhooked yearling horses. PROCEDURE: During the period from September 1998 through and April 1999, 20 horses had mild training failure (1 to 11 days lost), and 20 horses had severe training failure (13 to 108 days lost). Horses were assigned to these 2 groups on the basis of frequency distribution (median) of days lost during training. Horses were also categorized on the basis of type of training failure (planned vs nonplanned training failure). The outcome of primary interest was financial return. Median financial returns were compared among groups by use of the Mann-Whitney U test. RESULTS: Median financial returns for horses that had severe training failure ($1,000) were significantly different, compared with horses that had mild training failure ($24,000). Analysis of results also indicated that median returns were significantly different among horses that had planned training failure (-$2,000; eg, horses with radiographic abnormalities detected during routine prepurchase examinations that required surgical treatment, resulting in days lost during training), compared with horses that did not ($10,000). CONCLUSIONS AND CLINICAL RELEVANCE: Training failure has an economic impact on revenues in pinhooked yearling horses. Lameness, planned training failure, respiratory disease, and ringworm were common and important causes of training failure. |
Address |
Department of Large Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville 32610-0136, USA |
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ISSN |
0002-9645 |
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Notes |
PMID:11560271 |
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no |
Call Number |
Equine Behaviour @ team @ |
Serial |
4051 |
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Author |
Flack, J.C.; de Waal, F.B.M.; Krakauer, D.C. |
Title |
Social structure, robustness, and policing cost in a cognitively sophisticated species |
Type |
Journal Article |
Year |
2005 |
Publication |
The American Naturalist |
Abbreviated Journal |
Am Nat |
Volume |
165 |
Issue |
5 |
Pages |
E126-139 |
Keywords |
Animals; *Behavior, Animal; Cognition; Conflict (Psychology); Female; Macaca nemestrina/*physiology; Male; Models, Biological; *Social Behavior |
Abstract |
Conflict management is one of the primary requirements for social complexity. Of the many forms of conflict management, one of the rarest and most interesting is third-party policing, or intervening impartially to control conflict. Third-party policing should be hard to evolve because policers personally pay a cost for intervening, while the benefits are diffused over the whole group. In this study we investigate the incidence and costs of policing in a primate society. We report quantitative evidence of non-kin policing in the nonhuman primate, the pigtailed macaque. We find that policing is effective at reducing the intensity of or terminating conflict when performed by the most powerful individuals. We define a measure, social power consensus, that predicts effective low-cost interventions by powerful individuals and ineffective, relatively costly interventions by low-power individuals. Finally, we develop a simple probabilistic model to explore whether the degree to which policing can effectively reduce the societal cost of conflict is dependent on variance in the distribution of power. Our data and simple model suggest that third-party policing effectiveness and cost are dependent on power structure and might emerge only in societies with high variance in power. |
Address |
Santa Fe Institute, Santa Fe, New Mexico 87501, USA. jflack@santafe.edu |
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ISSN |
1537-5323 |
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Notes |
PMID:15795848 |
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no |
Call Number |
refbase @ user @ |
Serial |
168 |
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Author |
Cameron, E.Z.; du Toit, J.T. |
Title |
Winning by a neck: tall giraffes avoid competing with shorter browsers |
Type |
Journal Article |
Year |
2007 |
Publication |
The American naturalist |
Abbreviated Journal |
Am Nat |
Volume |
169 |
Issue |
1 |
Pages |
130-135 |
Keywords |
Acacia/growth & development; Animals; Feeding Behavior/*physiology; Neck/*anatomy & histology; Plant Leaves/growth & development; Ruminants/*anatomy & histology/*physiology; South Africa |
Abstract |
With their vertically elongated body form, giraffes generally feed above the level of other browsers within the savanna browsing guild, despite having access to foliage at lower levels. They ingest more leaf mass per bite when foraging high in the tree, perhaps because smaller, more selective browsers deplete shoots at lower levels or because trees differentially allocate resources to promote shoot growth in the upper canopy. We erected exclosures around individual Acacia nigrescens trees in the greater Kruger ecosystem, South Africa. After a complete growing season, we found no differences in leaf biomass per shoot across height zones in excluded trees but significant differences in control trees. We conclude that giraffes preferentially browse at high levels in the canopy to avoid competition with smaller browsers. Our findings are analogous with those from studies of grazing guilds and demonstrate that resource partitioning can be driven by competition when smaller foragers displace larger foragers from shared resources. This provides the first experimental support for the classic evolutionary hypothesis that vertical elongation of the giraffe body is an outcome of competition within the browsing ungulate guild. |
Address |
Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, Pretoria 0002, South Africa. ezcameron@zoology.up.ac.za |
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1537-5323 |
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Conference |
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Notes |
PMID:17206591 |
Approved |
no |
Call Number |
refbase @ user @ |
Serial |
410 |
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Author |
Dubois, F.; Giraldeau, L.-A.; Hamilton, I.M.; Grant, J.W.A.; Lefebvre, L. |
Title |
Distraction sneakers decrease the expected level of aggression within groups: a game-theoretic model |
Type |
Journal Article |
Year |
2004 |
Publication |
The American Naturalist |
Abbreviated Journal |
Am Nat |
Volume |
164 |
Issue |
2 |
Pages |
E32-45 |
Keywords |
*Aggression; Animals; Behavior, Animal/*physiology; Columbidae/*physiology; Competitive Behavior; Cooperative Behavior; *Game Theory; Hawks/*physiology; Models, Biological |
Abstract |
Hawk-dove games have been extensively used to predict the conditions under which group-living animals should defend their resources against potential usurpers. Typically, game-theoretic models on aggression consider that resource defense may entail energetic and injury costs. However, intruders may also take advantage of owners who are busy fighting to sneak access to unguarded resources, imposing thereby an additional cost on the use of the escalated hawk strategy. In this article we modify the two-strategy hawk-dove game into a three-strategy hawk-dove-sneaker game that incorporates a distraction-sneaking tactic, allowing us to explore its consequences on the expected level of aggression within groups. Our model predicts a lower proportion of hawks and hence lower frequencies of aggressive interactions within groups than do previous two-strategy hawk-dove games. The extent to which distraction sneakers decrease the frequency of aggression within groups, however, depends on whether they search only for opportunities to join resources uncovered by other group members or for both unchallenged resources and opportunities to usurp. |
Address |
Departement des Sciences Biologiques, Universite du Quebec a Montreal, Case postale 8888 Succursale Centre-Ville, Montreal, Quebec H3C 3P8, Canada. frede_dubois@yahoo.fr |
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1537-5323 |
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Conference |
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Notes |
PMID:15278850 |
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no |
Call Number |
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Serial |
2130 |
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Author |
Dubois, F.; Giraldeau, L.-A. |
Title |
The forager's dilemma: food sharing and food defense as risk-sensitive foraging options |
Type |
Journal Article |
Year |
2003 |
Publication |
The American Naturalist |
Abbreviated Journal |
Am Nat |
Volume |
162 |
Issue |
6 |
Pages |
768-779 |
Keywords |
Animals; Competitive Behavior/*physiology; *Environment; Feeding Behavior/*physiology; *Game Theory; *Models, Biological; Population Density; Population Dynamics |
Abstract |
Although many variants of the hawk-dove game predict the frequency at which group foraging animals should compete aggressively, none of them can explain why a large number of group foraging animals share food clumps without any overt aggression. One reason for this shortcoming is that hawk-dove games typically consider only a single contest, while most group foraging situations involve opponents that interact repeatedly over discovered food clumps. The present iterated hawk-dove game predicts that in situations that are analogous to a prisoner's dilemma, animals should share the resources without aggression, provided that the number of simultaneously available food clumps is sufficiently large and the number of competitors is relatively small. However, given that the expected gain of an aggressive animal is more variable than the gain expected by nonaggressive individuals, the predicted effect of the number of food items in a clump-clump richness-depends on whether only the mean or both the mean and variability associated with payoffs are considered. More precisely, the deterministic game predicts that aggression should increase with clump richness, whereas the stochastic risk-sensitive game predicts that the frequency of encounters resulting in aggression should peak at intermediate clump richnesses or decrease with increasing clump richness if animals show sensitivity to the variance or coefficient of variation, respectively. |
Address |
Departement des Sciences Biologiques, Universite du Quebec a Montreal, Case postale 8888, Succursale Centre-Ville, Montreal, Quebec H3C 3P8, Canada. fdubois@u-bourgogne.fr |
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ISSN |
0003-0147 |
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Notes |
PMID:14737714 |
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no |
Call Number |
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Serial |
2132 |
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Author |
Nettle, D. |
Title |
The evolution of personality variation in humans and other animals |
Type |
Journal Article |
Year |
2006 |
Publication |
The American Psychologist |
Abbreviated Journal |
Am Psychol |
Volume |
61 |
Issue |
6 |
Pages |
622-631 |
Keywords |
Animals; Birds; *Evolution; Female; Fishes; Humans; Insects; Male; Personality/*genetics/*physiology |
Abstract |
A comprehensive evolutionary framework for understanding the maintenance of heritable behavioral variation in humans is yet to be developed. Some evolutionary psychologists have argued that heritable variation will not be found in important, fitness-relevant characteristics because of the winnowing effect of natural selection. This article propounds the opposite view. Heritable variation is ubiquitous in all species, and there are a number of frameworks for understanding its persistence. The author argues that each of the Big Five dimensions of human personality can be seen as the result of a trade-off between different fitness costs and benefits. As there is no unconditionally optimal value of these trade-offs, it is to be expected that genetic diversity will be retained in the population. |
Address |
University of Newcastle, Newcastle, United Kingdom. daniel.nettle@ncl.ac.uk |
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0003-066X |
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PMID:16953749 |
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no |
Call Number |
Equine Behaviour @ team @ |
Serial |
4105 |
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Author |
Brosnan, S.F.; Freeman, C.; De Waal, F.B.M. |
Title |
Partner's behavior, not reward distribution, determines success in an unequal cooperative task in capuchin monkeys |
Type |
Journal Article |
Year |
2006 |
Publication |
American journal of primatology |
Abbreviated Journal |
Am. J. Primatol. |
Volume |
68 |
Issue |
7 |
Pages |
713-724 |
Keywords |
Animals; Behavior, Animal/*physiology; Cebus/*physiology; *Cooperative Behavior; Female; Food Preferences/physiology; Male; *Reward |
Abstract |
It was recently demonstrated that capuchin monkeys notice and respond to distributional inequity, a trait that has been proposed to support the evolution of cooperation in the human species. However, it is unknown how capuchins react to inequitable rewards in an unrestricted cooperative paradigm in which they may freely choose both whether to participate and, within the bounds of their partner's behavior, which reward they will receive for their participation. We tested capuchin monkeys with such a design, using a cooperative barpull, which has been used with great success in the past. Contrary to our expectations, the equity of the reward distribution did not affect success or pulling behavior. However, the behavior of the partner in an unequal situation did affect overall success rates: pairs that had a tendency to alternate which individual received the higher-value food in unequal reward situations were more than twice as successful in obtaining rewards than pairs in which one individual dominated the higher-value food. This ability to equitably distribute rewards in inherently biased cooperative situations has profound implications for activities such as group hunts, in which multiple individuals work together for a single, monopolizable reward. |
Address |
Living Links Center, Yerkes National Primate Research Center, Emory University, Atlanta, Georgia, USA. sbrosna@emory.edu |
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0275-2565 |
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PMID:16786518 |
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no |
Call Number |
refbase @ user @ |
Serial |
160 |
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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 |
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0275-2565 |
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PMID:16429416 |
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no |
Call Number |
refbase @ user @ |
Serial |
723 |
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Author |
Kendal, R.L.; Coe, R.L.; Laland, K.N. |
Title |
Age differences in neophilia, exploration, and innovation in family groups of callitrichid monkeys |
Type |
Journal Article |
Year |
2005 |
Publication |
American journal of primatology |
Abbreviated Journal |
Am. J. Primatol. |
Volume |
66 |
Issue |
2 |
Pages |
167-188 |
Keywords |
Age Factors; Analysis of Variance; Animals; *Animals, Zoo; Behavior, Animal/*physiology; Callitrichinae/*physiology; *Creativeness; Exploratory Behavior/*physiology; Observation; Social Behavior; Task Performance and Analysis |
Abstract |
The prevailing assumption in the primate literature is that young or juvenile primates are more innovative than adult individuals. This innovative tendency among the young is frequently thought to be a consequence, or side effect, of their increased rates of exploration and play. Conversely, Reader and Laland's [International Journal of Primatology 22:787-806, 2001] review of the primate innovation literature noted a greater reported incidence of innovation in adults than nonadults, which they interpreted as (in part) a reflection of the greater experience and competence of older individuals. Within callitrichids there is contradictory evidence for age differences in response to novel objects, foods, and foraging tasks. By presenting novel extractive foraging tasks to family groups of callitrichid monkeys in zoos, we examined, in a large sample, whether there are positive or negative relationships of age with neophilia, exploration, and innovation, and whether play or experience most facilitates innovation. The results indicate that exploration and innovation (but not neophilia) are positively correlated with age, perhaps reflecting adults' greater manipulative competence. To the extent that there was evidence for play in younger individuals, it did not appear to contribute to innovation. The implications of these findings for the fields of innovation and conservation through reintroduction are considered. |
Address |
Sub-Department of Animal Behavior, University of Cambridge, Cambridge, UK. RachelKendal2003@yahoo.co.uk |
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0275-2565 |
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PMID:15940712 |
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no |
Call Number |
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2148 |
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Author |
Mallavarapu, S.; Stoinski, T.S.; Bloomsmith, M.A.; Maple, T.L. |
Title |
Postconflict behavior in captive western lowland gorillas (Gorilla gorilla gorilla) |
Type |
Journal Article |
Year |
2006 |
Publication |
American journal of primatology |
Abbreviated Journal |
Am. J. Primatol. |
Volume |
68 |
Issue |
8 |
Pages |
789-801 |
Keywords |
Animals; *Behavior, Animal; *Competitive Behavior; Conflict (Psychology); Female; Gorilla gorilla/*physiology/psychology; Male; Time Factors |
Abstract |
Postconflict (PC) behaviors, including reconciliation and consolation, have been observed in many primate and several nonprimate species. Using the PC-matched control (MC) method, PC behavior was examined in two groups (n=13) of captive western lowland gorillas, a species for which no conflict resolution data have been published. Analyses of 223 conflicts showed significantly more affiliation between former opponents after a conflict when compared to control periods, indicating reconciliation. Results also showed significantly more affiliation between the victim and a third-party after a conflict, indicating consolation. Both solicited and unsolicited consolation were observed. The majority of the affiliative interactions observed for both reconciliation and consolation were social proximity, which suggests that unlike most nonhuman primates, proximity, rather than physical contact, may be the main mechanism for resolving conflicts in western lowland gorillas. PC behavior was not uniform throughout the groups, but rather varied according to dyad type. |
Address |
Zoo Atlanta, Atlanta, Georgia 30315, USA. smallavarapu@zooatlanta.org |
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0275-2565 |
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PMID:16847973 |
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refbase @ user @ |
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2873 |
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