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Author (up) Heitor, F.; do Mar Oom, M.; Vicente, L.
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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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:16815645 Approved no
Call Number refbase @ user @ Serial 292
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Author (up) Heitor, F.; do Mar Oom, M.; Vicente, L.
Title Social relationships in a herd of Sorraia horses: Part II. Factors affecting affiliative relationships and sexual behaviours Type Journal Article
Year 2006 Publication Behavioural Processes Abbreviated Journal Behav. Process.
Volume 73 Issue 3 Pages 231-239
Keywords Horse; Equus; Affiliative relationship; Rank; Kinship; Aggressiveness
Abstract The influence of age, dominance rank, kinship and aggressiveness over affiliative relationships and sexual behaviours were analysed in a herd of Sorraia horses, Equus caballus, kept under extensive management. Subjects were 10 adult mares 5-18 years old that had known each other since birth, and a stallion introduced into the group for breeding for the first time. Kinship coefficient and dominance rank were the most important factors affecting affiliative relationships. Bonds were reciprocal and stronger among mares with higher kinship. Mares spent more time in proximity to close-ranking and lower-ranking females. Mares with stronger affiliative relationships or higher relatedness were not less aggressive towards each other. Affiliative relationships between the stallion and the mares were not reciprocal: lower-ranking mares formed stronger bonds with the stallion but he preferred the less genetically related mares for proximity. However, the stallion was involved in sexual behaviours more frequently with the mares that were more genetically related to him. These results suggest that kinship beyond close relatives may affect affiliative relationships both among familiar and among unfamiliar horses. However, the influence of kinship does not imply that horses possess a kin recognition system and alternative explanations are discussed.
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Notes Approved no
Call Number refbase @ user @ Serial 462
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Author (up) Heitor, F.; Vicente, L.
Title Maternal care and foal social relationships in a herd of Sorraia horses: Influence of maternal rank and experience Type Journal Article
Year 2008 Publication Applied Animal Behaviour Science Abbreviated Journal Appl. Anim. Behav. Sci.
Volume 113 Issue 1-3 Pages 189-205
Keywords Horse; Rank; Experience; Maternal care; Social relationships
Abstract The influence of maternal rank and experience on patterns of maternal care and social relationships of foals were investigated in a managed herd of Sorraia horses, Equus caballus. Social interactions and spatial relationships of 13 foals (seven females and six males) born to seven mares were examined from birth to 10 months of life, within the three major periods of foal development. Conflict over suckling between dam and foal was not generally affected by rank and experience, but higher-ranking mothers allowed more suckling during late lactation than lower-ranking mothers. Foals of higher-ranking mares spent more time in proximity to the mother during socialization. Maternal rank and experience did not significantly affect maternal protectiveness, foal independence from the mother or the development of affiliative relationships between foals and group members. Foals of higher-ranking mares received lower frequencies of aggression from other horses only in the first month of life. Dominance relationships among foals depended mainly on aggressiveness and were not associated with maternal rank. The large variability in maternal behaviour, the absence of a significant association between maternal rank and body condition at parturition and the stable social environment within this herd may partly account for the reported results.
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Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0168-1591 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Equine Behaviour @ team @ Serial 4778
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Author (up) Heitor, F.; Vicente, L.
Title Learning about horses: What is equine learning all about? Type Journal Article
Year 2007 Publication Behavioural Processes Abbreviated Journal Behav. Process.
Volume 76 Issue 1 Pages 34-36
Keywords
Abstract
Address
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Publisher Place of Publication Editor
Language Summary Language Original Title
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Area Expedition Conference
Notes Approved no
Call Number refbase @ user @ Serial 627
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Author (up) Heleski, C.R.; Shelle, A.C.; Nielsen, B.D.; Zanella, A.J.
Title Influence of housing on weanling horse behavior and subsequent welfare Type Journal Article
Year 2002 Publication Applied Animal Behaviour Science Abbreviated Journal Appl. Anim. Behav. Sci.
Volume 78 Issue 2-4 Pages 291-302
Keywords Horse behavior; Weaning; Housing; Welfare; Time budget
Abstract Weaning foals marks a stressful event in horses' lives. Limited research exists regarding different housing methods post-weaning and the long-term implications on horse behavior and welfare. The purpose of this study was to monitor behavior and physiological stress markers in horses weaned individually in solid partition box stalls versus horses weaned in small groups and housed in paddocks. Both treatment groups underwent maternal deprivation stress, but the stalled weanlings had the additive effects of social isolation which prevented them from performing social behaviors. Quarter Horse weanlings from the Michigan State University, Merillat Equine Center, average age 4.5 months, were weaned in 13.4 m2 box stalls (n=6) or in groups of three in a 992 m2 paddock, which had very limited grazing forage and an open shelter available (n=6). Subjects were fed concentrate and hay to National Research Council recommendations. A time budget for 31 observed behaviors was developed. Behavioral observations were made 2 days per week, approximately 6 h per day, for the duration of the 56 days study. Instantaneous samples were recorded every 5 min on each observation day, with equal division between the two treatment groups (n=35 scans per horse per observation day). Focal data were recorded continuously between scans to provide a more detailed ethogram. On each observation day, fecal samples were collected to measure 11,17-dioxoandrostanes, an indicator of glucocorticoid metabolite concentration. Regarding the fecal 11,17-dioxoandrostanes, there was no discernible treatment difference either immediately post-weaning or at the conclusion of the 56 days study. Interestingly, all 12 weanlings showed a 4 week post-weaning increase in 11,17-dioxoandrostanes. The reason for this peak was unclear. Behavioral observations demonstrated a significantly different time budget in paddock-housed weanlings than in stall-housed weanlings (P<0.0001). Paddock-housed weanlings displayed a time budget more like a feral horse time budget, showing more time spent moving and less time spent lying. Paddock-housed weanlings, who had the option of selectively engaging in a broader range of behaviors, showed strong motivation to graze and be near conspecifics. Stalled weanlings spent significantly more time engaged in aberrant behaviors: licking or chewing the stall/shed wall, kicking at the stall/shed wall, pawing, and bucking/rearing bouts (P<0.03). Based on the variety of behaviors shown, the ability to engage in strongly preferred behaviors, and freedom from aberrant behavior, we conclude that the paddock-reared, group-housed weanlings had better welfare. However, there was insufficient evidence to conclude that the stalled weanlings had poor welfare.
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Notes Approved no
Call Number Equine Behaviour @ team @ Serial 3629
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Author (up) Hemelrijk, C.K.
Title Despotic societies, sexual attraction and the emergence of male 'tolerance': an agent-based model Type Journal Article
Year 2002 Publication Behaviour Abbreviated Journal Behaviour
Volume 139 Issue 6 Pages 729-747
Keywords
Abstract During the period when females are sexually attractive – but only then – males of certain species of primates, such as chimpanzees, allow females access to resources. Because males are usually dominant over females, such male 'tolerance' is explained as a special, reproductive strategy to gain access to females. In this paper a simpler hypothesis is proposed on the basis of an individual-based model (called DomWorld): male 'tolerance' towards females arises in 'despotic' artificial societies as a kind of 'respectful timidity', because sexual attraction automatically increases female dominance over males as a side-effect. The model consists in a homogeneous, virtual world with agents that group and perform dominance-interactions in which the effects of victory and defeat are self-reinforcing. The artificial sexes differ in that VirtualMales have a higher intensity of aggression, they start with a greater capacity to win conflicts than VirtualFemales and they are especially attracted to the opposite sex during certain periods, whereas VirtualFemales are not. I shall explain how the introduction into DomWorld of the attraction of VirtualMales by VirtualFemales leads to female dominance, why it does so only in despotic, but not in egalitarian societies, and how it leads to other phenomena that are relevant to the study of primate behaviour.
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Notes Approved no
Call Number refbase @ user @ Serial 864
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Author (up) Hemelrijk, C.K.
Title Towards the integration of social dominance and spatial structure Type Journal Article
Year 2000 Publication Animal Behaviour. Abbreviated Journal Anim. Behav.
Volume 59 Issue 5 Pages 1035-1048
Keywords
Abstract My aim was to show how individual-oriented (or artificial life) models may provide an integrative background for the development of theories about dominance by including effects of spatial structure. Dominance interactions are thought to serve two different, contrasting functions: acquisition of high rank and reduction of aggression. The model I present consists of a homogeneous virtual world inhabited by artificial agents whose actions are restricted to grouping and dominance interactions in which the effects of winning and losing are self-reinforcing. The two functions are implemented as strategies to initiate dominance interactions and the intensity of aggression and dominance perception (direct or memory based) are varied experimentally. Behaviour is studied by recording the same behavioural units as in real animals. Ranks appear to differentiate more clearly at high than at low intensity of aggression and also more in the case of direct than of memory-based rank perception. Strong differentiation of rank produces a cascade of unexpected effects that differ depending on which function is implemented: for instance, a decline in aggression, spatial centrality of dominants and a correlation between rank and aggression. Insight into the origination of these self-organized patterns leads to new hypotheses for the study of the social behaviour of real animals.
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Language Summary Language Original Title
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Notes Approved no
Call Number refbase @ user @ Serial 863
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Author (up) Hemelrijk, C.K.
Title Models of, and tests for, reciprocity, unidirectionality and other social interaction patterns at a group level Type Journal Article
Year 1990 Publication Animal Behaviour. Abbreviated Journal Anim. Behav.
Volume 39 Issue 6 Pages 1013-1029
Keywords
Abstract Research on reciprocity is impaired by confusing definitions and often wrongly used statistical tests. Here, two models of the mechanism on which reciprocity may be based are discussed and an initial step towards a new fremework for its analysis is presented. A distinction is made between reciprocity and interchange. In the case of reciprocity, for one kind of act the same kind is received in return. In interchange, however, two different kinds of acts are bartered. Three types of reciprocity/interchange in social actions among all pairs of group-members are distinguished ([`]qualitative', [`]relative' and [`]absolute') on the basis of the precision of the reciprocity/interchange. Permutation procedures for association between matrices (such as the Mantel Z and two other newly derived tests) are used as a statistical test for detecting reciprocity/interchange. A rough comparison of the power of the two new tests is included. The tests can be applied to all kinds of group-living animals and to all sorts of social behaviour. The distinction between the three types of reciprocity/interchange and the matching statistical methods are also useful for defining and detecting other patterns in social interactions, like unidirectionality and associations between different kinds of social behaviour. The influence on social interactions of variables like dominance rank, age and sex can be analysed in the three forms by testing correlations between invented matrices which represent the influence of these variables (the so-called hypothesis matrices) and social interaction matrices. These methods are extended for two categories of individuals, thus allowing the investigation of, for example, reciprocity between males and females. The methods are illustrated with examples of coalition formation and grooming behaviour among captive chimpanzees, Pan troglodytes.
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Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0003-3472 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Equine Behaviour @ team @ Serial 5049
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Author (up) Hemelrijk,C. K.; Wantia,J.; Gygax,L.
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 (up) Henry, S.; Hemery, D.; Richard, M.-A.; Hausberger, M.
Title Human-mare relationships and behaviour of foals toward humans Type Journal Article
Year 2005 Publication Applied Animal Behaviour Science Abbreviated Journal Appl. Anim. Behav. Sci.
Volume 93 Issue 3-4 Pages 341-362
Keywords Horse; Human-animal relationship; Maternal influence; Early experience; Social facilitation
Abstract We studied experimentally whether horse dams influenced foals' relationships with humans. We investigated the influence of the establishment of positive human-mare relationships on foals' behaviour toward humans. Forty-one foals and their dams were involved in this experiment. Half of the mares were softly brushed and fed by hand during a short period (total of 1.25 h) during the first 5 days of their foals' lives (experimental group, n = 21). The other mares were not handled experimentally and their foals received no contact with the experimenter (control group, n = 20). The reactions of both experimental and control foals were recorded under various conditions, first, for 5 min in the presence of a motionless experimenter, when foals were 15 and 30-35 days old, then in an approach test when they were 15 days old and in a saddle-pad tolerance test when they were 30-35 days old. Finally, approach-stroking tests were performed successively by the familiar experimenter when foals were 11-13 months old and by an unfamiliar person when they were 13-15 months old. Several observations strongly suggest that mares can influence their foals' behaviour toward humans: (1) during the handling procedure, experimental foals of protective mares were further from the handler than foals of calm mares (p < 0.001); (2) experimental foals remained, at all ages, closer to the experimenter (p < 0.05) and initiated more physical contacts (sniffing, licking, etc.) with the experimenter (p < 0.05) than control foals; (3) avoidance and flight responses of experimental foals were considerably reduced during approaches by the experimenter (p < 0.01) and they accepted saddle-pads on their backs more easily (p < 0.01) and more quickly (p < 0.01) than control foals. Lastly, the consequences of handling mares had effects that lasted at least until foals were one year old (p < 0.05) and became generalized from experimenter to unfamiliar humans, who could approach and stroke experimental foals rapidly during a test (p < 0.05). This is the first report of an attempt to use observation of mother by foals to facilitate human-foal relationships. The procedure is simple, takes little time and can easily be applied to any dam-foal pair, as it is not intrusive and presents no risks of disrupting mare-foal bonds.
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Language Summary Language Original Title
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Notes Approved no
Call Number refbase @ user @ Serial 331
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