| Records |
| Author |
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 |
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Series Issue |
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Edition |
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| ISSN |
0376-6357 |
ISBN |
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Expedition |
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Conference |
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| Notes |
PMID:16815645 |
Approved |
no |
Call Number  |
refbase @ user @ |
Serial |
292 |
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| Author |
Cameron, E.Z. |
| Title |
Facultative adjustment of mammalian sex ratios in support of the Trivers-Willard hypothesis: evidence for a mechanism |
Type |
Journal Article |
| Year |
2004 |
Publication |
Proceedings. Biological sciences / The Royal Society |
Abbreviated Journal |
Proc Biol Sci |
| Volume |
271 |
Issue |
1549 |
Pages |
1723-1728 |
| Keywords |
Age Factors; Animals; Body Constitution; *Evolution; Female; Glucose/metabolism/physiology; Litter Size; Male; Mammals/*physiology; *Models, Biological; Reproduction/physiology; Seasons; Sex Factors; *Sex Ratio; Time Factors |
| Abstract |
Evolutionary theory predicts that mothers of different condition should adjust the birth sex ratio of their offspring in relation to future reproductive benefits. Published studies addressing variation in mammalian sex ratios have produced surprisingly contradictory results. Explaining the source of such variation has been a challenge for sex-ratio theory, not least because no mechanism for sex-ratio adjustment is known. I conducted a meta-analysis of previous mammalian sex-ratio studies to determine if there are any overall patterns in sex-ratio variation. The contradictory nature of previous results was confirmed. However, studies that investigated indices of condition around conception show almost unanimous support for the prediction that mothers in good condition bias their litters towards sons. Recent research on the role of glucose in reproductive functioning have shown that excess glucose favours the development of male blastocysts, providing a potential mechanism for sex-ratio variation in relation to maternal condition around conception. Furthermore, many of the conflicting results from studies on sex-ratio adjustment would be explained if glucose levels in utero during early cell division contributed to the determination of offspring sex ratios. |
| 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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English |
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Series Issue |
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Edition |
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| ISSN |
0962-8452 |
ISBN |
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Expedition |
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Conference |
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| Notes |
PMID:15306293 |
Approved |
no |
| Call Number |
refbase @ user @ |
Serial |
413 |
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| Author |
Fischer, J.; Hammerschmidt, K.; Cheney, D.L.; Seyfarth, R.M. |
| Title |
Acoustic features of male baboon loud calls: influences of context, age, and individuality |
Type |
Journal Article |
| Year |
2002 |
Publication |
The Journal of the Acoustical Society of America |
Abbreviated Journal |
J Acoust Soc Am |
| Volume |
111 |
Issue |
3 |
Pages |
1465-1474 |
| Keywords |
Age Factors; Animal Communication; Animals; Individuality; Male; *Papio; *Social Environment; *Sound Spectrography; *Vocalization, Animal |
| Abstract |
The acoustic structure of loud calls (“wahoos”) recorded from free-ranging male baboons (Papio cynocephalus ursinus) in the Moremi Game Reserve, Botswana, was examined for differences between and within contexts, using calls given in response to predators (alarm wahoos), during male contests (contest wahoos), and when a male had become separated from the group (contact wahoos). Calls were recorded from adolescent, subadult, and adult males. In addition, male alarm calls were compared with those recorded from females. Despite their superficial acoustic similarity, the analysis revealed a number of significant differences between alarm, contest, and contact wahoos. Contest wahoos are given at a much higher rate, exhibit lower frequency characteristics, have a longer “hoo” duration, and a relatively louder “hoo” portion than alarm wahoos. Contact wahoos are acoustically similar to contest wahoos, but are given at a much lower rate. Both alarm and contest wahoos also exhibit significant differences among individuals. Some of the acoustic features that vary in relation to age and sex presumably reflect differences in body size, whereas others are possibly related to male stamina and endurance. The finding that calls serving markedly different functions constitute variants of the same general call type suggests that the vocal production in nonhuman primates is evolutionarily constrained. |
| Address |
Department of Psychology, University of Pennsylvania, Philadelphia 19104, USA. fischer@eva.mpg.de |
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English |
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Series Issue |
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Edition |
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| ISSN |
0001-4966 |
ISBN |
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Expedition |
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Conference |
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| Notes |
PMID:11931324 |
Approved |
no |
| Call Number |
refbase @ user @ |
Serial |
691 |
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| Author |
Harkins, J.D.; Kamerling, S.G.; Church, G. |
| Title |
Effect of competition on performance of thoroughbred racehorses |
Type |
Journal Article |
| Year |
1992 |
Publication |
Journal of Applied Physiology (Bethesda, Md. : 1985) |
Abbreviated Journal |
J Appl Physiol |
| Volume |
72 |
Issue |
3 |
Pages |
836-841 |
| Keywords |
Age Factors; Animals; Anxiety/physiopathology; Competitive Behavior/*physiology; Exertion/*physiology; Fatigue/physiopathology; Female; Heart Rate; Horses/*physiology; Lactates/blood; Lactic Acid; Male; Sex Characteristics |
| Abstract |
The effect of competition and the influence of age and sex on performance were examined in a study of 18 Thoroughbred racehorses. The horses performed two solo and two competitive runs at 1,200 and 1,600 m for a total of eight runs. No group ran faster during competition, which may have been a reflection of the quality of horses used for this study and their susceptibility to stress-induced impairment of performance. Males showed no significant difference between competitive and solo run times, whereas females were consistently slower during competition. Males ran significantly faster than females in all runs. There was no difference in run times due to age, which may have been due to the high mean age (5.9 yr) of the group. The slower competitive run times may have occurred because of an earlier onset of fatigue when compared with solo runs. Plasma lactate was significantly greater for the 1,200-m competitive than for the solo runs. |
| Address |
Department of Veterinary Physiology, Pharmacology, and Toxicology, School of Veterinary Medicine, Louisiana State University, Baton Rouge 70803 |
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English |
Summary Language |
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Series Issue |
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Edition |
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| ISSN |
8750-7587 |
ISBN |
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Medium |
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Conference |
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| Notes |
PMID:1568979 |
Approved |
no |
| Call Number |
refbase @ user @ |
Serial |
1947 |
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| Author |
Feist, J.D.; McCullough, D.R. |
| Title |
Reproduction in feral horses |
Type |
Journal Article |
| Year |
1975 |
Publication |
Journal of Reproduction and Fertility. Supplement |
Abbreviated Journal |
J Reprod Fertil Suppl |
| Volume |
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Issue |
23 |
Pages |
13-18 |
| Keywords |
Age Factors; Animals; Female; Horses/*physiology; Leadership; Male; Maternal Behavior; Population; Reproduction; *Sexual Behavior, Animal; Social Dominance; Sucking Behavior |
| Abstract |
A behavioural study of feral horses was conducted on the Pryor Mountain Wild Horse Range in the western United States. All 270 horses on the Range were identified individually. The sex ratio was nearly balanced. Foal to adult female ratio was 43-2:100. Morality was concentrated among foals and old horses. Horses were organized as forty-four harem groups each with a dominant stallion, one to two immature stallions, one to three immature mares, one to three adult mares and their yearling and foal offspring, and 23 bachelor groups of one to eight stallions. Harem groups were quite stable year-round because of dominance and leadership by the stallions and group fidelity by mares and their offsring. Most changes occurred during the breeding season and involved immature females. Defeat of dominant stallions was infrequent. Immature males were tolerated because of their submissive behaviour. Bachelor stallion groups were inherently unstable. Mares came into heat after foaling in May/June, and were mated by harem stallions only. |
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English |
Summary Language |
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Abbreviated Series Title |
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Series Issue |
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Edition |
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| ISSN |
0449-3087 |
ISBN |
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Conference |
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| Notes |
PMID:1060766 |
Approved |
no |
| Call Number |
refbase @ user @ |
Serial |
1964 |
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| Author |
Call, J. |
| Title |
Inferences by exclusion in the great apes: the effect of age and species |
Type |
Journal Article |
| Year |
2006 |
Publication |
Animal Cognition |
Abbreviated Journal |
Anim. Cogn. |
| Volume |
9 |
Issue |
4 |
Pages |
393-403 |
| Keywords |
Age Factors; Animals; Association Learning; *Cognition; *Concept Formation; *Discrimination Learning; Female; Gorilla gorilla; Hominidae/classification/*psychology; Male; Pan paniscus; Pan troglodytes; Pongo pygmaeus; *Problem Solving; Species Specificity |
| Abstract |
This study investigated the ability of chimpanzees, gorillas, orangutans, and bonobos to make inferences by exclusion using the procedure pioneered by Premack and Premack (Cognition 50:347-362, 1994) with chimpanzees. Thirty apes were presented with two different food items (banana vs. grape) on a platform and covered with identical containers. One of the items was removed from the container and placed between the two containers so that subjects could see it. After discarding this item, subjects could select between the two containers. In Experiment 1, apes preferentially selected the container that held the item that the experimenter had not discarded, especially if subjects saw the experimenter remove the item from the container (but without seeing the container empty). Experiment 3 in which the food was removed from one of the containers behind a barrier confirmed these results. In contrast, subjects performed at chance levels when a stimulus (colored plastic chip: Exp. 1; food item: Exp. 2 and Exp. 3) designated the item that had been removed. These results indicated that apes made inferences, not just learned to use a discriminative cue to avoid the empty container. Apes perceived and treated the item discarded by the experimenter as if it were the very one that had been hidden under the container. Results suggested a positive relationship between age and inferential ability independent of memory ability but no species differences. |
| Address |
Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, 04103, Leipzig, Germany. call@eva.mpg.de |
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English |
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Edition |
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| ISSN |
1435-9448 |
ISBN |
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Conference |
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| Notes |
PMID:16924458 |
Approved |
no |
| Call Number |
Equine Behaviour @ team @ |
Serial |
2444 |
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| Author |
Borsari, A.; Ottoni, E.B. |
| Title |
Preliminary observations of tool use in captive hyacinth macaws (Anodorhynchus hyacinthinus) |
Type |
Journal Article |
| Year |
2005 |
Publication |
Animal Cognition |
Abbreviated Journal |
Anim. Cogn. |
| Volume |
8 |
Issue |
1 |
Pages |
48-52 |
| Keywords |
Age Factors; Animals; *Feeding Behavior; Female; *Intelligence; Male; *Motor Skills; *Nuts; *Parrots |
| Abstract |
Many animals use tools (detached objects applied to another object to produce an alteration in shape, position, or structure) in foraging, for instance, to access encapsulated food. Descriptions of tool use by hyacinth macaws (Anodorhynchus hyacinthinus) are scarce and brief. In order to describe one case of such behavior, six captive birds were observed while feeding. Differences in nut manipulation and opening proficiency between adults and juveniles were recorded. The tools may be serving as a wedge, preventing the nut from slipping and/or rotating, reducing the impact of opening, or providing mechanical aid in its positioning and/or use of force. Data suggest that birds of this species have an innate tendency to use objects (tools) as aids during nut manipulation and opening. |
| Address |
Laboratory of Cognitive Ethology, Department of Experimental Psychology, Institute of Psychology, University of Sao Paulo, Sao Paulo, Brazil. borsari@hotmail.com |
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English |
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1435-9448 |
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| Notes |
PMID:15248094 |
Approved |
no |
| Call Number |
Equine Behaviour @ team @ |
Serial |
2518 |
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| Author |
Imura, T.; Tomonaga, M. |
| Title |
Perception of depth from shading in infant chimpanzees ( Pan troglodytes) |
Type |
Journal Article |
| Year |
2003 |
Publication |
Animal Cognition |
Abbreviated Journal |
Anim. Cogn. |
| Volume |
6 |
Issue |
4 |
Pages |
253-258 |
| Keywords |
Age Factors; Animals; Contrast Sensitivity/*physiology; Depth Perception/*physiology; Discrimination Learning/*physiology; Female; Male; Pan troglodytes/growth & development/*physiology/*psychology; Pattern Recognition, Visual/physiology |
| Abstract |
We investigated the ability to perceive depth from shading, one of the pictorial depth cues, in three chimpanzee infants aged 4-10 months old, using a preferential reaching task commonly used to study pictorial depth perception in human infants. The chimpanzee infants reached significantly more to three-dimensional toys than to pictures thereof and more to the three-dimensional convex than to the concave. Furthermore, two of the three infants reached significantly more to the photographic convex than to the photographic concave. These infants also looked longer at the photographic convex than the concave. Our results suggest that chimpanzees perceive, at least as early as the latter half of the first year of life, pictorial depth defined by shading information. Photographic convexes contain richer information about pictorial depth (e.g., attached shadow, cast shadow, highlighted area, and global difference in brightness) than simple computer-graphic graded patterns. These cues together might facilitate the infants' perception of depth from shading. |
| Address |
Graduate School of Humanities, Kwansei Gakuin University, Uegahara, Nishinomiya, Hyogo 662-8501, Japan |
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English |
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| ISSN |
1435-9448 |
ISBN |
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Conference |
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| Notes |
PMID:14610661 |
Approved |
no |
| Call Number |
Equine Behaviour @ team @ |
Serial |
2550 |
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| Author |
Hayashi, M.; Matsuzawa, T. |
| Title |
Cognitive development in object manipulation by infant chimpanzees |
Type |
Journal Article |
| Year |
2003 |
Publication |
Animal Cognition |
Abbreviated Journal |
Anim. Cogn. |
| Volume |
6 |
Issue |
4 |
Pages |
225-233 |
| Keywords |
Age Factors; Animals; Child Development/physiology; Child, Preschool; Cognition/*physiology; Female; Growth; Humans; Imitative Behavior/physiology; Infant; Learning/*physiology; Male; Mothers/*psychology; Motor Skills/*physiology; Pan troglodytes/*growth & development/*psychology; Psychomotor Performance/*physiology; Species Specificity |
| Abstract |
This study focuses on the development of spontaneous object manipulation in three infant chimpanzees during their first 2 years of life. The three infants were raised by their biological mothers who lived among a group of chimpanzees. A human tester conducted a series of cognitive tests in a triadic situation where mothers collaborated with the researcher during the testing of the infants. Four tasks were presented, taken from normative studies of cognitive development of Japanese infants: inserting objects into corresponding holes in a box, seriating nesting cups, inserting variously shaped objects into corresponding holes in a template, and stacking up wooden blocks. The mothers had already acquired skills to perform these manipulation tasks. The infants were free to observe the mothers' manipulative behavior from immediately after birth. We focused on object-object combinations that were made spontaneously by the infant chimpanzees, without providing food reinforcement for any specific behavior that the infants performed. The three main findings can be summarized as follows. First, there was precocious appearance of object-object combination in infant chimpanzees: the age of onset (8-11 months) was comparable to that in humans (around 10 months old). Second, object-object combinations in chimpanzees remained at a low frequency between 11 and 16 months, then increased dramatically at the age of approximately 1.5 years. At the same time, the accuracy of these object-object combinations also increased. Third, chimpanzee infants showed inserting behavior frequently and from an early age but they did not exhibit stacking behavior during their first 2 years of life, in clear contrast to human data. |
| Address |
Section of Language and Intelligence, Primate Research Institute, Kyoto University, 41 Kanrin, Inuyama, 484-8506 Aichi, Japan. misato@pri.kyoto-u.ac.jp |
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English |
Summary Language |
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Abbreviated Series Title |
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Series Issue |
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Edition |
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1435-9448 |
ISBN |
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| Notes |
PMID:12905079 |
Approved |
no |
| Call Number |
Equine Behaviour @ team @ |
Serial |
2559 |
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| Author |
Bjorklund, D.F.; Yunger, J.L.; Bering, J.M.; Ragan, P. |
| Title |
The generalization of deferred imitation in enculturated chimpanzees (Pan troglodytes) |
Type |
Journal Article |
| Year |
2002 |
Publication |
Animal Cognition |
Abbreviated Journal |
Anim. Cogn. |
| Volume |
5 |
Issue |
1 |
Pages |
49-58 |
| Keywords |
Age Factors; Animals; Behavior, Animal; Humans; *Imitative Behavior; Pan troglodytes/physiology/*psychology; Parenting; Species Specificity |
| Abstract |
Deferred imitation of object-related actions and generalization of imitation to similar but not identical tasks was assessed in three human-reared (enculturated) chimpanzees, ranging in age from 5 to 9 years. Each ape displayed high levels of deferred imitation and only slightly lower levels of generalization of imitation. The youngest two chimpanzees were more apt to generalize the model's actions when they had displayed portions of the target behaviors at baseline, consistent with the idea that learning is more likely to occur when working within the “zone of proximal development.” We argue that generalization of imitation is the best evidence to date of imitative learning in chimpanzees. |
| Address |
Department of Psychology, Florida Atlantic University, 777 Glades Road, Boca Raton, FL 33431-0991, USA. dbjorklund@fau.edu |
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English |
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Series Title |
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Edition |
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1435-9448 |
ISBN |
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Conference |
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| Notes |
PMID:11957402 |
Approved |
no |
| Call Number |
Equine Behaviour @ team @ |
Serial |
2610 |
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