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Author Bouskila, A.; de Vries, H.; Hermans, Z.M.; van Dierendonck, M.
Title Leadership roles in movements of free-roaming Konik horses (Equus caballus) in a Dutch reserve Type Conference Article
Year 2012 Publication Proceedings of the 2. International Equine Science Meeting Abbreviated Journal Proc. 2. Int. Equine. Sci. Mtg
Volume in press Issue Pages
Keywords
Abstract We observed the activity and movements of Konik horses (Equus caballus) in order to determine the initiators of movements and the individuals taking the lead in movements of the main groups. We conducted our observations between March-June 2010 along the shores of the Rhine river, in the Blauwe Kamer reserve, in the Netherlands. The horses were introduced to the reserve alongside with cattle to prevent the growth of the forest and maintain the grass habitat. We videotaped all observations on two digital video cameras, one providing the general view of the group and the other scanning and focusing on the individuals, to aid with identification. Horses were recognized based on individual profiles that were created for each one, consisting of photos of both sides and notes of the main characters, such as orientation and coloration of the mane, prominent scars and markings, etc. Twenty three horses (not counting foals) were organized in two harem groups with 11 individuals (two of which were dominant stallions) in the large group and six individuals (one of which was a stallion) in the second group. These two main groups were always within sight of each other, and two bachelor males moved usually in their vicinity. An additional group of three young bachelor males roamed elsewhere in the reserve. We divided the movements of the horses to local movements while grazing and to long-distance movements, in which the horses moved to a different grazing location, to a pond of water, resting area or groups of trees that were used by the horses for scratching themselves. During the local movements, any two of the three oldest females in the large harem group were enough to cause the whole group to follow them and gradually change position within the pasture. The smaller harem always followed the large harem’s movements. The long-distance movements of the large harem were sometimes initiated by one of the harem stallions that herded their group and at other times – by the oldest females. Soon after the movement was clearly initiated, the dominant stallions positioned themselves in the back of the group or in the center and had no influence on the direction of move that was only determined by the leading females. In the long-distance movements too, the small harem followed the large harem group, and the two bachelor males usually followed behind them. Social interactions included aggressive interactions between the two dominant males within the large harem or between dominant stallions and the two bachelor males accompanying the two harems. In addition, dominant males courting or attempting to mate with mares sometimes caused a turmoil that eventually initiated movement of the harems. KW -
Address
Corporate Author Bouskila, A. Thesis
Publisher Xenophon Publishing Place of Publication Wald Editor Krueger, K.;
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (down) 978-3-9808134-26 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Equine Behaviour @ team @ Serial 5592
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Author Wich, S.A.; de Vries, H.
Title Male monkeys remember which group members have given alarm calls Type Journal Article
Year 2006 Publication Proceedings. Biological Sciences / The Royal Society Abbreviated Journal Proc Biol Sci
Volume 273 Issue 1587 Pages 735-740
Keywords Animals; Behavior, Animal/*physiology; Cercopithecidae/*physiology/*psychology; Cognition/physiology; Fear/physiology/*psychology; Female; Indonesia; Male; Vocalization, Animal/*physiology
Abstract Primates give alarm calls in response to the presence of predators. In some species, such as the Thomas langur (Presbytis thomasi), males only emit alarm calls if there is an audience. An unanswered question is whether the audience's behaviour influences how long the male will continue his alarm calling. We tested three hypotheses that might explain the alarm calling duration of male Thomas langurs: the fatigue, group size and group member behaviour hypotheses. Fatigue and group size did not influence male alarm calling duration. We found that males only ceased calling shortly after all individuals in his group had given at least one alarm call. This shows that males keep track of and thus remember which group members have called.
Address Behavioural Biology, Utrecht University, Padualaan 14, 3584 Utrecht, The Netherlands. s.a.wich@bio.uu.nl
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 (down) 0962-8452 ISBN Medium
Area Expedition Conference
Notes PMID:16608694 Approved no
Call Number Equine Behaviour @ team @ Serial 2816
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Author VanDierendonck, M.C.; de Vries, H.; Schilder, M.B.H.; Colenbrander, B.; Þorhallsdóttir, A.G. and Sigurjónsdóttir, H.
Title Interventions in social behaviour in a herd of mares and geldings Type Journal Article
Year 2009 Publication Applied Animal Behaviour Science Abbreviated Journal Appl. Anim. Behav. Sci.
Volume 116 Issue 1 Pages 67-73
Keywords Horses; Social relationships; Interventions; Mares; Geldings; Play; Allogrooming; Social network
Abstract Social dynamics and maintenance of social cohesion were studied by analysing social interventions in two groups of horses consisting of adult mares, their offspring, adult geldings and sub-adults. The animals were observed for a total of 1316 h. All relevant dyadic and triadic social interactions, including initial behaviour, possible intervention and outcome, were recorded. The main question was: do horses use interventions in affiliative interactions to safeguard their social network? Horses were significantly more likely to intervene in allogrooming or play interactions that involved a preferred partner. The stronger the preferred association in allogrooming, the higher the likelihood the intervener took over allogrooming with an initial dyad member. Interveners originating from two newly introduced groups (n = 3 and 5), intervened significantly more often when a member of their own group allogroomed with an unfamiliar horse. In play, no correlation with unfamiliarity was found. Overall, the intervening horses stopped more than half of the initial allogrooming interactions, and a third of all interactions. Therefore, social facilitation cannot sufficiently explain interference behaviour. This study shows that maintaining relationships with preferred partners is important to horses and has implications for equine husbandry and management.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (down) 0168-1591 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Equine Behaviour @ team @ Serial 4766
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Author VanDierendonck, M.C.; de Vries, H.; Schilder, M.B.H.
Title An Analysis of Dominance, Its Behavioural Parameters and Possible Determinants in a Herd of Icelandic orses in Captivity Type Journal Article
Year 1995 Publication Netherlands Journal of Zoology Abbreviated Journal Netherl. J. Zool.
Volume 45 Issue 3-4 Pages 362-385
Keywords Dominance; rank order; horses; Icelandic horses.
Abstract Th e applicability of the concept of dominance was investigated in a captive herd of  Icelandic

horses and  ponies of diff erent breeds. Eight out of  behaviours possibly related

to dominance occurred frequently enough to be investigated in detail. For these eight agonistic

behaviours the coverage, the unidirectionality in the exchange, and the degree of

transitivity (Landau`s linearity index) were calculated. Four off ensive behaviours, together

with avoidance, were suitable for further analysis with regard to dominance. Th e patterns

of asymmetries with which these behaviours were exchanged were suffi ciently similar as to

justify the application of the dominance concept and to construct a (nearly) linear dominance

hierarchy. Th e rank order of the castrated stallions was completely linear, the hierarchy

of the mares was almost completely linear. Th e results suggest that off ensive and defensive

aggressive behaviours should be treated separately and that the concept of dominance

is applicable. However, ritualized formal dominance signals between adult horses appear to

be (almost) absent. Th e rank positions of the individuals were correlated with age and residency

in the herd but not with height. Middle ranking horses tended to be more frequently

in the close vicinity of another horse than high ranking or low ranking horses. Over and

above this correlation at the individual level, it was found that pairs of horses close in rank

to each other were more often also spatially close to each other. Being in oestrus did not infl

uence the dominance relationships between mares. For castrated stallions the rank positions

were correlated with the age at which they were castrated. Th is suggests that in male

horses experience prior to neutering infl uences the behaviour afterwards.
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Corporate Author Thesis
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Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
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ISSN (down) ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number refbase @ user @ Serial 440
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Author Gammell, M.P.; de Vries, H.; Jennings, D.J.; Carlin, C.M.; Hayden, T.J.
Title David's score: a more appropriate dominance ranking method than Clutton-Brock et al.'s index Type Journal Article
Year 2003 Publication Animal Behaviour. Abbreviated Journal Anim. Behav.
Volume 66 Issue 3 Pages 601-605
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Corporate Author Thesis
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Language Summary Language Original Title
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Notes Approved no
Call Number refbase @ user @ Serial 453
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Author de Vries, H.; Stevens, J.M.G.; Vervaecke, H.
Title Measuring and testing the steepness of dominance hierarchies Type Journal Article
Year 2006 Publication Animal Behaviour. Abbreviated Journal Anim. Behav.
Volume 71 Issue 3 Pages 585-592
Keywords
Abstract In the analysis of social dominance in groups of animals, linearity has been used by many researchers as the main structural characteristic of a dominance hierarchy. In this paper we propose, alongside linearity, a quantitative measure for another property of a dominance hierarchy, namely its steepness. Steepness of a hierarchy is defined here as the absolute slope of the straight line fitted to the normalized David's scores (calculated on the basis of a dyadic dominance index corrected for chance) plotted against the subjects' ranks. This correction for chance is an improvement of an earlier proposal by de Vries (appendix 2 in de Vries, Animal Behaviour, 1998, 55, 827-843). In addition, we present a randomization procedure for determining the statistical significance of a hierarchy's steepness, which can be used to test the observed steepness against the steepness expected under the null hypothesis of random win chances for all pairs of individuals. Whereas linearity depends on the number of established binary dominance relationships and the degree of transitivity in these relationships, steepness measures the degree to which individuals differ from each other in winning dominance encounters. Linearity and steepness are complementary measures to characterize a dominance hierarchy.
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Language Summary Language Original Title
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Notes Approved no
Call Number refbase @ user @ Serial 454
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Author de VRIES, H.A.N.
Title Finding a dominance order most consistent with a linear hierarchy: a new procedure and review Type Journal Article
Year 1998 Publication Animal Behaviour. Abbreviated Journal Anim. Behav.
Volume 55 Issue 4 Pages 827-843
Keywords
Abstract A procedure for ordering a set of individuals into a linear or near-linear dominance hierarchy is presented. Two criteria are used in a prioritized way in reorganizing the dominance matrix to find an order that is most consistent with a linear hierarchy: first, minimization of the numbers of inconsistencies and, second, minimization of the total strength of the inconsistencies. The linear ordering procedure, which involves an iterative algorithm based on a generalized swapping rule, is feasible for matrices of up to 80 individuals. The procedure can be applied to any dominance matrix, since it does not make any assumptions about the form of the probabilities of winning and losing. The only assumption is the existence of a linear or near-linear hierarchy which can be verified by means of a linearity test. A review of existing ranking methods is presented and these are compared with the proposed method.
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Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
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Area Expedition Conference
Notes Approved no
Call Number refbase @ user @ Serial 457
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Author Albers, P.C.H.; de Vries, H.
Title Elo-rating as a tool in the sequential estimation of dominance strengths Type Journal Article
Year 2001 Publication Animal Behaviour. Abbreviated Journal Anim. Behav.
Volume 61 Issue 2 Pages 489-495
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Notes Approved no
Call Number refbase @ user @ Serial 858
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Author De Vries, H.; Appleby, M.C.
Title Finding an appropriate order for a hierarchy: a comparison of the I&SI and the BBS methods Type Journal Article
Year 2000 Publication Animal Behaviour. Abbreviated Journal Anim. Behav.
Volume 59 Issue 1 Pages 239-245
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Language Summary Language Original Title
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Notes Approved no
Call Number refbase @ user @ Serial 869
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Author Vervaecke, H.; Stevens, J.; Vandemoortele, H.; Sigurjönsdöttir, H.; De Vries, H.
Title Aggression and dominance in matched groups of subadult Icelandic horses (Equus caballus) Type Journal Article
Year 2007 Publication Journal of Ethology Abbreviated Journal J. Ethol.
Volume 25 Issue 3 Pages 239-248
Keywords Equus – Dominance – Aggression – Hierarchy – Steepness
Abstract Abstract  We studied sex differences in the nature of aggression and dominance behaviour in two newly formed groups of 1-year-old Icelandic horses. One herd contained nine geldings, the other nine mares. The groups were matched with regard to dominance-determining traits such as age, weaning age, composition of native herd, social experience, genetic origin, body condition and maternal dominance status. High-ranking individuals of both sexes were more aggressive, high-ranking males were older, and high-ranking females had a better body condition. Frequencies of aggressions were similar in both groups. The mares reacted significantly more by showing submission upon an aggression rather than by not responding or by escalating the aggression. For the geldings, this difference was not observed due to a lower tendency to submit. A linear dominance hierarchy was found in both groups. David`s scores provided additional information regarding cardinal rank distances and were used to calculate steepness of hierarchies. The female hierarchy was somewhat steeper compared to the male hierarchy, suggesting somewhat lower despotism among males. This was mainly a consequence of the lower unidirectionality in male submission. Male contests occurred predominantly between dyads at top and mid positions, suggesting a low degree of acceptance of the hierarchy.
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Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
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Area Expedition Conference
Notes Approved no
Call Number Equine Behaviour @ team @ Serial 2192
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