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Author Rogers, C.W.; Davies, A.S.; Pfeiffer, D.U.; Davie, P.S.
Title (up) Linear and temporal stride characteristics of 3-day event horses at a CCI*** 3-day event horse inspection Type Journal Article
Year 1999 Publication New Zealand Veterinary Journal Abbreviated Journal N Z Vet J
Volume 47 Issue 6 Pages 193-197
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Abstract AIMS: To quantify the linear and temporal characteristics of the trot of 3-day event horses during the preliminary horse inspection of an advanced grade CCI* 3-day event. METHODS: A cross sectional study was made of the kinematics of 24 3-day-event horses during the first horse inspection at a CCI* level S-day event. Video footage was digitised and linear and temporal measurements were made. RESULTS: The horses trotted for an average of 10.44+/-1.55 strides. Spatial measurements were made on an average of 5.66+/-0.92 consecutive strides when the horses were within the calibration zone. The horses increased and then obtained a constant velocity within the calibration zone. Trotting on the asphalt track did not alter the relationships between stride length, stride duration and velocity when compared with previously published values. Horse-specific differences in stance and retraction percentages were identified. CONCLUSION: Horse specific differences were identified that may contribute to each horse's unique gait or kinematic fingerprint. It is proposed that the initiation of, and completion of, stance by the hind limb first may represent engagement of the hind quarters and be a response to dressage training.
Address Equine Research, New Zealand
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ISSN 0048-0169 ISBN Medium
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Notes PMID:16032102 Approved no
Call Number Equine Behaviour @ team @ Serial 3714
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Author Timney, B.; Keil, K.
Title (up) Local and global stereopsis in the horse Type Journal Article
Year 1999 Publication Vision Research Abbreviated Journal Vision Res
Volume 39 Issue 10 Pages 1861-1867
Keywords Animals; Depth Perception/*physiology; Female; Horses/*physiology; Pattern Recognition, Visual/physiology; Psychophysics; Sensory Thresholds/physiology; Vision, Binocular/physiology; Vision, Monocular/physiology
Abstract Although horses have laterally-placed eyes, there is substantial binocular overlap, allowing for the possibility that these animals have stereopsis. In the first experiment of the present study we measured local stereopsis by obtaining monocular and binocular depth thresholds for renal depth stimuli. On all measures, the horses' binocular performance was superior to their monocular. When depth thresholds were obtained, binocular thresholds were several times superior to those obtained monocularly, suggesting that the animals could use stereoscopic information when it was available. The binocular thresholds averaged about 15 min arc. In the second experiment we obtained evidence for the presence of global stereopsis by testing the animals' ability to discriminate between random-dot stereograms with and without consistent disparity information. When presented with such stimuli they showed a strong preference for the cyclopean equivalent of the positive stimulus with the real depth. These results provide the first behavioral demonstration of a full range of stereoscopic skills in a lateral-eyed mammal.
Address Department of Psychology, Faculty of Social Science, University of Western Ontario, London, Canada. timney@julian.uwo.ca
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ISSN 0042-6989 ISBN Medium
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Notes PMID:10343877 Approved yes
Call Number Equine Behaviour @ team @ Serial 3580
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Author Pattison, P.; Wasserman, S.
Title (up) Logit models and logistic regressions for social networks: II. Multivariate relations Type Journal Article
Year 1999 Publication The British Journal of Mathematical and Statistical Psychology Abbreviated Journal Br J Math Stat Psychol
Volume 52 ( Pt 2) Issue Pages 169-193
Keywords Humans; Markov Chains; *Models, Statistical; Organization and Administration; *Social Support
Abstract The research described here builds on our previous work by generalizing the univariate models described there to models for multivariate relations. This family, labelled p*, generalizes the Markov random graphs of Frank and Strauss, which were further developed by them and others, building on Besag's ideas on estimation. These models were first used to model random variables embedded in lattices by Ising, and have been quite common in the study of spatial data. Here, they are applied to the statistical analysis of multigraphs, in general, and the analysis of multivariate social networks, in particular. In this paper, we show how to formulate models for multivariate social networks by considering a range of theoretical claims about social structure. We illustrate the models by developing structural models for several multivariate networks.
Address Department of Psychology, University of Melbourne, Parkville, Victoria, Australia. pattision@psych.unimelb.edu.au
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Language English Summary Language Original Title
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Series Volume Series Issue Edition
ISSN 0007-1102 ISBN Medium
Area Expedition Conference
Notes PMID:10613111 Approved no
Call Number Equine Behaviour @ team @ Serial 5030
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Author Drea, C.M.; Wallen, K.
Title (up) Low-status monkeys “play dumb” when learning in mixed social groups Type Journal Article
Year 1999 Publication Proceedings of the National Academy of Sciences of the United States of America Abbreviated Journal Proc. Natl. Acad. Sci. U.S.A.
Volume 96 Issue 22 Pages 12965-12969
Keywords
Abstract Many primates, including humans, live in complex hierarchical societies where social context and status affect daily life. Nevertheless, primate learning studies typically test single animals in limited laboratory settings where the important effects of social interactions and relationships cannot be studied. To investigate the impact of sociality on associative learning, we compared the individual performances of group-tested rhesus monkeys (Macaca mulatta) across various social contexts. We used a traditional discrimination paradigm that measures an animal's ability to form associations between cues and the obtaining of food in choice situations; but we adapted the task for group testing. After training a 55-member colony to separate on command into two subgroups, composed of either high- or low-status families, we exposed animals to two color discrimination problems, one with all monkeys present (combined condition), the other in their “dominant” and “subordinate” cohorts (split condition). Next, we manipulated learning history by testing animals on the same problems, but with the social contexts reversed. Monkeys from dominant families excelled in all conditions, but subordinates performed well in the split condition only, regardless of learning history. Subordinate animals had learned the associations, but expressed their knowledge only when segregated from higher-ranking animals. Because aggressive behavior was rare, performance deficits probably reflected voluntary inhibition. This experimental evidence of rank-related, social modulation of performance calls for greater consideration of social factors when assessing learning and may also have relevance for the evaluation of human scholastic achievement.
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Notes 10.1073/pnas.96.22.12965 Approved no
Call Number Serial 2093
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Author Macuda, T.; Timney, B.
Title (up) Luminance and chromatic discrimination in the horse (Equus caballus) Type Journal Article
Year 1999 Publication Behavioural Processes Abbreviated Journal Behav. Process.
Volume 44 Issue 3 Pages 301-307
Keywords Colour vision; Chromatic discrimination; Luminance discrimination; Horse
Abstract Equine colour vision was measured under conditions that minimised the possibility of animals using brightness cues to make chromatic discriminations. In a two-stage study, we first obtained luminance discrimination functions for achromatic targets then tested for chromatic discrimination over a range of target luminances. Horses were trained on a two-choice discrimination task. The positive stimulus was varied in luminance and/or colour using neutral density and broad band colour filters. The negative stimulus appeared as a uniform grey. In the brightness discrimination task, the horses performed well at large luminance differences but their percentage of correct responses declined to near chance levels at differences of less than 0.2 log units. In addition, a decrement in performance was noted at luminance differences of less than 0.2 log units for green and yellow chromatic discrimination functions, suggesting that horses cannot easily discriminate yellow and green from grey. However, the chromatic discrimination functions for red and blue showed that animals performed very well across the full range of target luminances. These results suggest that horses are at least dichromats.
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Notes Approved no
Call Number refbase @ user @ Serial 844
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Author Hedrick, P.W.; Parker, K.M.; Miller, E.L.; Miller, P.S.
Title (up) Major Histocompatibility Complex Variation in the Endangered Przewalski's Horse Type Journal Article
Year 1999 Publication Genetics Abbreviated Journal Genetics
Volume 152 Issue 4 Pages 1701-1710
Keywords
Abstract The major histocompatibility complex (MHC) is a fundamental part of the vertebrate immune system, and the high variability in many MHC genes is thought to play an essential role in recognition of parasites. The Przewalski's horse is extinct in the wild and all the living individuals descend from 13 founders, most of whom were captured around the turn of the century. One of the primary genetic concerns in endangered species is whether they have ample adaptive variation to respond to novel selective factors. In examining 14 Przewalski's horses that are broadly representative of the living animals, we found six different class II DRB major histocompatibility sequences. The sequences showed extensive nonsynonymous variation, concentrated in the putative antigen-binding sites, and little synonymous variation. Individuals had from two to four sequences as determined by single-stranded conformation polymorphism (SSCP) analysis. On the basis of the SSCP data, phylogenetic analysis of the nucleotide sequences, and segregation in a family group, we conclude that four of these sequences are from one gene (although one sequence codes for a nonfunctional allele because it contains a stop codon) and two other sequences are from another gene. The position of the stop codon is at the same amino-acid position as in a closely related sequence from the domestic horse. Because other organisms have extensive variation at homologous loci, the Przewalski's horse may have quite low variation in this important adaptive region. N1 -
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Notes Approved no
Call Number Equine Behaviour @ team @ Serial 5043
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Author Silk, J.B.
Title (up) Male bonnet macaques use information about third-party rank relationships to recruit allies Type Journal Article
Year 1999 Publication Animal Behaviour. Abbreviated Journal Anim. Behav.
Volume 58 Issue 1 Pages 45-51
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Abstract Social challenges may have driven the evolution of intelligence in primates and other taxa. In primates, the social intelligence hypothesis is supported by evidence that primates know a lot about their own relationships to others and also know something about the nature of relationships among other individuals (third-party relationships). Knowledge of third-party relationships is likely to play an especially important role in coalitions, which occur when one individual intervenes in an ongoing dispute involving other group members, by helping individuals to predict who will support or intervene against them when they are fighting with particular opponents, and to assess which potential allies are likely to be effective in coalitions against their opponents. To date, however, there is no evidence that primates make use of knowledge of third-party relationships when they form coalitions. Here, I show that male bonnet macaques, Macaca radiata , use information about third-party rank relationships when they recruit support from other males. Males consistently chose allies that outranked themselves and their opponents, and made such choices considerably more often than would be expected by chance alone. The analysis shows that the data do not fit simpler explanations based upon males' knowledge of their own relationships to other males or males' ability to recognize powerful allies.
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Notes Approved no
Call Number Equine Behaviour @ team @ Serial 2870
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Author Asa, C.S.
Title (up) Male reproductive success in free-ranging feral horses Type Journal Article
Year 1999 Publication Abbreviated Journal Behavioral Ecology and Sociobiology
Volume 47 Issue 1-2 Pages 89-93
Keywords Key words Reproductive success; Alternative mating strategies; Mating systems; Paternity
Abstract In the social organization of feral horses, adult males compete to monopolize groups or bands of females, sometimes called harems. Alternative male strategies are to remain alone or with other bachelors or, less commonly, to accept subordinate status within a harem. The hypothesis that dominant harem stallion status confers a reproductive advantage was tested in free-ranging feral horses. The presence of foals in harems headed by vasectomized (VSX) versus intact stallions was used to assess the ability of these stallions to control reproduction in their harems. Of harems headed by VSX stallions, 17 and 33% contained foals during years 2 and 3 post-treatment, respectively. In contrast, 86 and 80% of harems headed by non-VSX stallions contained foals in those years. Acquisition of pregnant mares appeared more likely than sneak copulations by bachelor stallions to account for foals in harems with a single stallion. However, most foals were born into harems that included a subordinate stallion, an occurrence that was undoubtedly exacerbated by the extended breeding season resulting from the sterility of the harem stallion. Thus, in comparing alternative reproductive tactics, bachelors appeared less successful than subordinate stallions within a harem. However, the highest reproductive success was achieved by the harem stallion, further demonstrating that alternative tactics are not equally profitable.
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Publisher Springer-Verlag Place of Publication Editor
Language English Summary Language Original Title
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ISSN 0340-5443 ISBN Medium
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Notes Approved no
Call Number Equine Behaviour @ team @ Serial 5786
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Author White, D.J.; Galef Jr, B.G.
Title (up) Mate choice copying and conspecific cueing in Japanese quail,Coturnix coturnix japonica Type Journal Article
Year 1999 Publication Animal Behaviour. Abbreviated Journal Anim. Behav.
Volume 57 Issue 2 Pages 465-473
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Notes Approved no
Call Number Serial 1811
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Author Slagsvold, T.; Viljugrein, H.
Title (up) Mate choice copying versus preference for actively displaying males by female pied flycatchers Type Journal Article
Year 1999 Publication Animal Behaviour. Abbreviated Journal Anim. Behav.
Volume 57 Issue 3 Pages 679-686
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Notes Approved no
Call Number Serial 1810
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