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Author Sigurjónsdóttir, H.; Haraldsson, H. url  doi
openurl 
  Title Significance of Group Composition for the Welfare of Pastured Horses Type Journal Article
  Year 2019 Publication Animals Abbreviated Journal Animals  
  Volume 9 Issue 14 Pages  
  Keywords horse welfare; aggression; allogrooming; pastured horses; Icelandic horse  
  Abstract We explore how herd composition and management factors correlate with frequencies of social interactions in horse groups. Since the welfare of horses correlates with low aggression levels and social contact opportunities, information of this kind is important. The data are a collection of records of social interactions of 426 Icelandic horses in 20 groups of at least eight horses. The complexities and limitations of the data prohibit useful statistical modelling so the results are presented descriptively. Interesting and informative patterns emerge which can be of use both in management and in future studies. Of special interest are the low levels of agonistic behaviours in breeding groups where one stallion was present. The horses were less agonistic when in groups with young foals and where group membership was stable. Unfamiliar yearlings in peer groups were especially aggressive. Allogrooming was most frequent in groups with relatively more young horses and in unstable and small groups. Interestingly, the horses allogroomed more if they had few preferred allogrooming partners. The findings show that composition (age/sex) and stability of groups are of great importance with respect to aggression levels and opportunities for establishing bonds.  
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  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title (down) Animals  
  Series Volume 9 Series Issue 1 Edition  
  ISSN 2076-2615 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Equine Behaviour @ team @ Serial 6510  
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Author Houpt, K.A.; Wolski, T.R. openurl 
  Title Stability of equine hierarchies and the prevention of dominance related aggression Type Journal Article
  Year 1980 Publication Equine veterinary journal Abbreviated Journal Equine Vet J  
  Volume 12 Issue 1 Pages 15-18  
  Keywords *Aggression; Animals; *Behavior, Animal; Feeding Behavior; Female; *Hierarchy, Social; *Horses; Humans; Male; Maternal Behavior; *Social Dominance  
  Abstract The dominance hierarchy of a herd of 10 Thoroughbred mares was determined twice, at an interval of 18 months, using paired feeding tests. Each mare's rank was correlated significantly between the 2 tests. This indicated that the hierarchy within the herd was stable. The offspring of dominant and subordinate mares were also tested for dominance in their own age groups. The offspring of dominant mares tended to be near the top of the hierarchy while those of middle and low ranking mares were not consistently found in the middle or bottom of their own hierarchies. Paired feeding tests were carried out on 8 ponies. During tests the time that each pony spent eating and the ponies' aggressive interactions were recorded. Two situations were used. Each pony-pair was tested when both ponies were in the same paddock and also when they were separated by a rail fence. The subordinate ponies spent significantly more time eating and the domonant pony was significantly less aggressive, when the pony-pair was separated by a fence than when they were in one paddock. It was concluded that the dominance hierarchies of adult horse groups changed very little over time and that the foals of dominant mares will tend to be dominant in their own age groups. Management practices can be used to reduce aggression and consequent injury that may arise in group feeding situations.  
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  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title (down)  
  Series Volume Series Issue Edition  
  ISSN 0425-1644 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:7189148 Approved no  
  Call Number refbase @ user @ Serial 59  
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Author de Waal, F.B. openurl 
  Title Primates--A natural heritage of conflict resolution Type Journal Article
  Year 2000 Publication Science (New York, N.Y.) Abbreviated Journal Science  
  Volume 289 Issue 5479 Pages 586-590  
  Keywords Aggression/*psychology; Animals; Behavior, Animal; *Conflict (Psychology); Female; Humans; Male; *Primates; *Social Behavior; Social Dominance  
  Abstract The traditional notion of aggression as an antisocial instinct is being replaced by a framework that considers it a tool of competition and negotiation. When survival depends on mutual assistance, the expression of aggression is constrained by the need to maintain beneficial relationships. Moreover, evolution has produced ways of countering its disruptive consequences. For example, chimpanzees kiss and embrace after fights, and other nonhuman primates engage in similar “reconciliations.” Theoretical developments in this field carry implications for human aggression research. From families to high schools, aggressive conflict is subject to the same constraints known of cooperative animal societies. It is only when social relationships are valued that one can expect the full complement of natural checks and balances.  
  Address Living Links, Center for the Advanced Study of Human and Ape Evolution, Yerkes Regional Primate Research Center, and Psychology Department, Emory University, Atlanta, GA 30322, USA. dewaal@emory.edu  
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  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title (down)  
  Series Volume Series Issue Edition  
  ISSN 0036-8075 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:10915614 Approved no  
  Call Number refbase @ user @ Serial 187  
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Author Baker, K.C.; Seres, E.; Aureli, F.; De Waal, F.B. doi  openurl
  Title Injury risks among chimpanzees in three housing conditions Type Journal Article
  Year 2000 Publication American journal of primatology Abbreviated Journal Am. J. Primatol.  
  Volume 51 Issue 3 Pages 161-175  
  Keywords Aggression; *Animal Welfare; Animals; Female; *Housing, Animal; Male; *Pan troglodytes; Risk Assessment; Wounds and Injuries/*veterinary  
  Abstract Meeting the psychological needs of chimpanzees (Pan troglodytes) can be a challenge given their aggressiveness on the one hand and the complexity of their social lives on the other. It is unclear how to balance the need to provide opportunities for species-appropriate behavior against potential risks of injury chimpanzees may inflict on each other. This study evaluates the suggestion that simpler social environments protect chimpanzees from wounding. Over a two-year period all visible injuries to 46 adult males, 64 adult females, and 25 immature chimpanzees were recorded at the Yerkes Regional Primate Research Center. Approximately half of the subjects were mother-reared, and the rest were nursery-reared. Housing included compounds containing about 20 chimpanzees, interconnected indoor-outdoor runs for groups of up to 12 individuals, and smaller indoor-outdoor runs for pairs and trios. Annual wounding rates were calculated for serious wounds (extensive injuries and all those requiring veterinary intervention) as well as for minor wounds. Compound-housed chimpanzees incurred the highest level of minor wounding, but serious wounding levels were not affected by housing condition. Even with a period of dominance instability and elevated levels of wounding in one compound, compound chimpanzees were not injured more than those in smaller social groups over the long term. Nursery-reared females in moderate-sized groups were wounded more than mother-reared females. Also, nursery-reared males and females were wounded less often when paired with mother-reared companions. Overall, this study indicates that maintaining chimpanzees in pairs and trios would not be an effective means for reducing injuries. The management of wounding in chimpanzee colonies is influenced more by the sex and rearing composition of a colony.  
  Address Living Links Center, Yerkes Regional Primate Research Center, Emory University, Atlanta, Georgia 30322, USA. kateb@rmy.emory.edu  
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  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title (down)  
  Series Volume Series Issue Edition  
  ISSN 0275-2565 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:10902665 Approved no  
  Call Number refbase @ user @ Serial 188  
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Author Aureli, F.; de Waal, F.B. doi  openurl
  Title Inhibition of social behavior in chimpanzees under high-density conditions Type Journal Article
  Year 1997 Publication American journal of primatology Abbreviated Journal Am. J. Primatol.  
  Volume 41 Issue 3 Pages 213-228  
  Keywords Aggression/*psychology; Animals; *Behavior, Animal; *Crowding; Female; Male; Pan troglodytes/*psychology; Population Density; *Social Environment; Stress, Psychological  
  Abstract This is the first study to investigate the short-term effects of high population density on captive chimpanzees (Pan troglodytes). Subjects of the study were 45 chimpanzees living in five different groups at the Yerkes Regional Primate Research Center. The groups were observed under two conditions: 1) when they had access to both the indoor and outdoor sections of their enclosures; 2) during cold days when they were locked into the indoor runs, which reduced the available space by more than half. Under the high-density condition, allogrooming and submissive greetings decreased, but juvenile play increased. Remarkably, the rate of various forms of agonistic behavior, such as aggression, bluff charge, bluff display, and hooting, occurred less frequently under the high-density condition. This general decrease in adult social activity, including agonistic behavior, can be interpreted as an inhibition strategy to reduce opportunities for conflict when interindividual distances are reduced. This strategy is probably effective only in the short run, however. Behavioral indicators of anxiety, such as rough scratching and yawning, showed elevated rates, suggesting increased social tension under the high-density condition.  
  Address Yerkes Regional Primate Research Center, Emory University, Atlanta, GA 30322, USA  
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  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title (down)  
  Series Volume Series Issue Edition  
  ISSN 0275-2565 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:9057966 Approved no  
  Call Number refbase @ user @ Serial 203  
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Author Heitor, F.; do Mar Oom, M.; Vicente, L. doi  openurl
  Title Social relationships in a herd of Sorraia horses Part I. Correlates of social dominance and contexts of aggression Type Journal Article
  Year 2006 Publication Behavioural Processes Abbreviated Journal Behav. Process.  
  Volume 73 Issue 2 Pages 170-177  
  Keywords Age Factors; *Aggression; Animals; Female; *Hierarchy, Social; Horses/*psychology; Male; Sex Factors; *Social Dominance; *Social Environment; Statistics, Nonparametric  
  Abstract Factors related to dominance rank and the functions of aggression were studied in a herd of Sorraia horses, Equus caballus, under extensive management. Subjects were 10 adult mares 5-18 years old and a stallion introduced into the group for breeding. Dominance relationships among mares were clear, irrespective of rank difference, and remained stable after introduction of the stallion. The dominance hierarchy was significantly linear and rank was positively correlated with age and total aggressiveness. Higher-ranking mares received lower frequency and intensity of agonistic interactions. Nevertheless, higher-ranking dominants were not more likely to elicit submission from their subordinates than lower-ranking dominants. Neither close-ranking mares nor mares with less clear dominance relationships were more aggressive towards each other. Agonistic interactions seemed to be used more importantly in regulation of space than to obtain access to food or to reassert dominance relationships. Contexts of aggression were related to mare rank. The results suggest that dominance relationships based on age as a conventional criterion were established to reduce aggressiveness in a herd where the costs of aggression are likely to outweigh the benefits.  
  Address Centro de Biologia Ambiental, Faculdade de Ciencias da Universidade de Lisboa, Campo Grande, Edificio C2, 1749-016 Lisboa, Portugal  
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  Series Volume Series Issue Edition  
  ISSN 0376-6357 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:16815645 Approved no  
  Call Number refbase @ user @ Serial 292  
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Author Hemelrijk, C.K.; Wantia, J. doi  openurl
  Title Individual variation by self-organisation Type Journal Article
  Year 2005 Publication Neuroscience and biobehavioral reviews Abbreviated Journal Neurosci Biobehav Rev  
  Volume 29 Issue 1 Pages 125-136  
  Keywords Aggression; Animals; Behavior, Animal/*physiology; Competitive Behavior/*physiology; Female; Humans; *Individuality; Male; Models, Psychological; Sex Characteristics; *Social Dominance; Time Factors  
  Abstract In this paper, we show that differences in dominance and spatial centrality of individuals in a group may arise through self-organisation. Our instrument is a model, called DomWorld, that represents two traits that are often found in animals, namely grouping and competing. In this model individual differences grow under the following conditions: (1) when the intensity of aggression increases and grouping becomes denser, (2) when the degree of sexual dimorphism in fighting power increases. In this case the differences among females compared to males grow too, (3) when, upon encountering another individual, the tendency to attack is 'obligate' and not conditional, namely 'sensitive to risks'. Results resemble phenomena described for societies of primates, mice, birds and pigs.  
  Address Theoretical Biology, University of Groningen, NN Haren, The Netherlands. hemelrij@ifi.unizh.ch  
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  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title (down)  
  Series Volume Series Issue Edition  
  ISSN 0149-7634 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:15652260 Approved no  
  Call Number refbase @ user @ Serial 443  
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Author Hemelrijk,C. K.; Wantia,J.; Gygax,L. doi  openurl
  Title The construction of dominance order: comparing performance of five methods using an individual-based model Type Journal Article
  Year 2005 Publication Behaviour Abbreviated Journal Behaviour  
  Volume 142 Issue 8 Pages 1043-1064  
  Keywords dominance order, ranking method, agent-based model, statistical method, aggression  
  Abstract In studies of animal behaviour investigators correlate dominance with all kinds of behavioural

variables, such as reproductive success and foraging success. Many methods are used to

produce a dominance hierarchy from a matrix reflecting the frequency of winning dominance

interactions. These different methods produce different hierarchies. However, it is difficult to

decide which ranking method is best. In this paper, we offer a new procedure for this decision:

we use an individual-based model, called DomWorld, as a test-environment. We choose this

model, because it provides access to both the internal dominance values of artificial agents

(which reflects their fighting power) and the matrix of winning and losing among them and,

in addition, because its behavioural rules are biologically inspired and its group-level patterns

resemble those of real primates. We compare statistically the dominance hierarchy based on

the internal dominance values of the artificial agents with the dominance hierarchy produced

by ranking individuals by (a) their total frequency of winning, (b) their average dominance

index, (c) a refined dominance index, the David`s score, (d) the number of subordinates each

individual has and (e) a ranking method based on maximizing the linear order of the hierarchy.

Because dominance hierarchies may differ depending on group size, type of society, and the

interval of study, we compare these ranking methods for these conditions.We study complete

samples as well as samples randomly chosen to resemble the limitations of observing real

animals. It appears that two methods of medium complexity (the average dominance index

and David`s score) lead to hierarchical orders that come closest to the hierarchy based on

internal dominance values of the agents. We advocate usage of the average dominance index,

because of its computational simplicity.
 
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  Notes Approved no  
  Call Number refbase @ user @ Serial 445  
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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  
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  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 Earley, R.L.; Dugatkin, L.A. doi  openurl
  Title Eavesdropping on visual cues in green swordtail (Xiphophorus helleri) fights: a case for networking Type Journal Article
  Year 2002 Publication Proceedings. Biological sciences / The Royal Society Abbreviated Journal Proc Biol Sci  
  Volume 269 Issue 1494 Pages 943-952  
  Keywords *Aggression; Animals; *Behavior, Animal; *Cyprinodontiformes; Female; Male  
  Abstract Aggressive contests probably occur in networking environments where information about fighting ability is conveyed both to an opponent and to individuals peripheral to the fight itself, the bystanders. Our primary aim was to investigate the relative influences of eavesdropping and prior social experience on the dynamics of aggressive contests in Xiphophorus helleri. A bystander's ability to witness an encounter was manipulated using clear, one-way mirror, and opaque partitions. After watching (or not watching) the initial contest, the bystander encountered either the winner or loser of the bout. Treatment comparisons of bystander-winner or bystander-loser contest dynamics indicated the presence or absence of winner, loser, or eavesdropping effects. Winner and loser effects had negligible influences on bystander contest dynamics. Eavesdropping significantly reduced the bystander's propensity to initiate aggression, escalate, and win against seen winners regardless of whether the watched bout had escalated or not. Though eavesdropping had relatively little effect on bystander-loser contest dynamics, bystanders were less prone to initiate aggression and win against losers that had escalated in the witnessed bout. Thus, bystanders appear to preferentially retain and utilize information gained about potentially dangerous opponents (winners or persistent losers). Our data lend clear support for the importance of eavesdropping in visually based aggressive signalling systems.  
  Address Department of Biology, Life Science, Room 139, University of Louisville, Louisville, KY 40292, USA. rlearl01@athena.louisville.edu  
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  Series Volume Series Issue Edition  
  ISSN 0962-8452 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:12028778 Approved no  
  Call Number refbase @ user @ Serial 498  
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