Records |
Author |
Cameron, E.Z.; du Toit, J.T. |
Title |
Winning by a neck: tall giraffes avoid competing with shorter browsers |
Type |
Journal Article |
Year |
2007 |
Publication |
The American naturalist |
Abbreviated Journal |
Am Nat |
Volume |
169 |
Issue |
1 |
Pages |
130-135 |
Keywords |
Acacia/growth & development; Animals; Feeding Behavior/*physiology; Neck/*anatomy & histology; Plant Leaves/growth & development; Ruminants/*anatomy & histology/*physiology; South Africa |
Abstract |
With their vertically elongated body form, giraffes generally feed above the level of other browsers within the savanna browsing guild, despite having access to foliage at lower levels. They ingest more leaf mass per bite when foraging high in the tree, perhaps because smaller, more selective browsers deplete shoots at lower levels or because trees differentially allocate resources to promote shoot growth in the upper canopy. We erected exclosures around individual Acacia nigrescens trees in the greater Kruger ecosystem, South Africa. After a complete growing season, we found no differences in leaf biomass per shoot across height zones in excluded trees but significant differences in control trees. We conclude that giraffes preferentially browse at high levels in the canopy to avoid competition with smaller browsers. Our findings are analogous with those from studies of grazing guilds and demonstrate that resource partitioning can be driven by competition when smaller foragers displace larger foragers from shared resources. This provides the first experimental support for the classic evolutionary hypothesis that vertical elongation of the giraffe body is an outcome of competition within the browsing ungulate guild. |
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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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1537-5323 |
ISBN |
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Conference |
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Notes |
PMID:17206591 |
Approved |
no |
Call Number |
refbase @ user @ |
Serial |
410 |
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Author |
Dubois, F.; Giraldeau, L.-A. |
Title |
The forager's dilemma: food sharing and food defense as risk-sensitive foraging options |
Type |
Journal Article |
Year |
2003 |
Publication |
The American Naturalist |
Abbreviated Journal |
Am Nat |
Volume |
162 |
Issue |
6 |
Pages |
768-779 |
Keywords |
Animals; Competitive Behavior/*physiology; *Environment; Feeding Behavior/*physiology; *Game Theory; *Models, Biological; Population Density; Population Dynamics |
Abstract |
Although many variants of the hawk-dove game predict the frequency at which group foraging animals should compete aggressively, none of them can explain why a large number of group foraging animals share food clumps without any overt aggression. One reason for this shortcoming is that hawk-dove games typically consider only a single contest, while most group foraging situations involve opponents that interact repeatedly over discovered food clumps. The present iterated hawk-dove game predicts that in situations that are analogous to a prisoner's dilemma, animals should share the resources without aggression, provided that the number of simultaneously available food clumps is sufficiently large and the number of competitors is relatively small. However, given that the expected gain of an aggressive animal is more variable than the gain expected by nonaggressive individuals, the predicted effect of the number of food items in a clump-clump richness-depends on whether only the mean or both the mean and variability associated with payoffs are considered. More precisely, the deterministic game predicts that aggression should increase with clump richness, whereas the stochastic risk-sensitive game predicts that the frequency of encounters resulting in aggression should peak at intermediate clump richnesses or decrease with increasing clump richness if animals show sensitivity to the variance or coefficient of variation, respectively. |
Address |
Departement des Sciences Biologiques, Universite du Quebec a Montreal, Case postale 8888, Succursale Centre-Ville, Montreal, Quebec H3C 3P8, Canada. fdubois@u-bourgogne.fr |
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English |
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ISSN |
0003-0147 |
ISBN |
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Notes |
PMID:14737714 |
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no |
Call Number |
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Serial |
2132 |
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Author |
Overdorff, D.J.; Erhart, E.M.; Mutschler, T. |
Title |
Does female dominance facilitate feeding priority in black-and-white ruffed lemurs (Varecia variegata) in southeastern Madagascar? |
Type |
Journal Article |
Year |
2005 |
Publication |
American journal of primatology |
Abbreviated Journal |
Am. J. Primatol. |
Volume |
66 |
Issue |
1 |
Pages |
7-22 |
Keywords |
Agonistic Behavior; Animals; Eating/physiology; Feeding Behavior/*physiology; Female; Leadership; Lemuridae/*physiology; Madagascar; Male; Observation; Sex Factors; *Social Dominance |
Abstract |
Although many Malagasy lemurs are thought to be female dominant and to have female feeding priority, to date the relationship between these behaviors has been rigorously established only in Lemur catta, and other ways that females might achieve feeding priority have not been examined closely. Erhart and Overdorff [International Journal of Primatology 20:927-940, 1999] suggested that one way female primates achieve feeding priority is to initiate and lead groups to food, thereby gaining access to the food first and positively influencing their food intake compared to other group members. Here we describe female dominance patterns and potential measures of feeding priority in two groups of black-and-white ruffed lemurs (Varecia variegata) that were observed over a 15-month period in southeastern Madagascar. We predicted that the females would 1) be consistently dominant to males, 2) lead groups to food sources more often than males, and 3) have higher feeding rates compared to males when they arrived at food sources first. The results were dissimilar between the study groups. During the study, the oldest adult female in group 1 died. There was no evidence for female dominance in this group, and the remaining (likely natal) female did not lead the group more often, nor did she have a higher food intake than males. Group 1 dispersed shortly after the time frame reported here. In contrast, the resident female in group 2 was dominant to group males (based on agonistic interactions), led the group to food sources more often, and experienced a higher food intake when she arrived first at a food source. How these patterns vary over time and are influenced by the number of females in groups, group stability, food quality, and reproductive condition will be examined in future analyses. |
Address |
Department of Anthropology, University of Texas, Austin, Texas 78712-1086, USA. overdorff@mail.utexas.edu |
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English |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0275-2565 |
ISBN |
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Medium |
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Area |
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Conference |
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Notes |
PMID:15898069 |
Approved |
no |
Call Number |
Equine Behaviour @ team @ |
Serial |
4110 |
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Author |
Tommasi, L.; Polli, C. |
Title |
Representation of two geometric features of the environment in the domestic chick ( Gallus gallus) |
Type |
Journal Article |
Year |
2004 |
Publication |
Animal Cognition |
Abbreviated Journal |
Anim. Cogn. |
Volume |
7 |
Issue |
1 |
Pages |
53-59 |
Keywords |
Animals; Chickens/*physiology; *Cues; Feeding Behavior/*physiology; Male; Pattern Recognition, Visual/*physiology |
Abstract |
We report experiments based on a novel test in domestic chicks ( Gallus gallus), designed to examine the encoding of two different geometric features of an enclosed environment: relative lengths of the walls and amplitude of the corners. Chicks were trained to search for a food reward located in one corner of a parallelogram-shaped enclosure. Between trials, chicks were passively disoriented and the enclosure was rotated, making reorientation possible only on the basis of the internal spatial structure of the enclosure. In order to reorient, chicks could rely on two sources of information: the relative lengths of the walls of the enclosure (associated to their left-right sense order) and the angles subtended by walls at corners. Chicks learned the task choosing equally often the reinforced corner and its rotational equivalent. Results of tests carried out in novel enclosures, the shapes of which were chosen ad hoc (1) to induce reorientation based only on the ratio of walls lengths plus sense (rectangular enclosure), or (2) to induce reorientation based only on corner angles (rhombus-shaped enclosure), suggested that chicks encoded both features of the environment. In a third test, in which chicks faced a conflict between these geometric features (mirror parallelogram-shaped enclosure), reorientation seemed to depend on the salience of corner angles. These results shed light on the elements of the environmental geometry which control spatial reorientation, and broaden the knowledge on the geometric representation of space in animals. |
Address |
Department of General Psychology, University of Padua, Via Venezia 8, 35131 Padua, Italy. ltommasi@unipd.it |
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English |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1435-9448 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
PMID:12884079 |
Approved |
no |
Call Number |
Equine Behaviour @ team @ |
Serial |
2561 |
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Author |
Emery, N.J.; Dally, J.M.; Clayton, N.S. |
Title |
Western scrub-jays ( Aphelocoma californica) use cognitive strategies to protect their caches from thieving conspecifics |
Type |
Journal Article |
Year |
2004 |
Publication |
Animal Cognition |
Abbreviated Journal |
Anim. Cogn. |
Volume |
7 |
Issue |
1 |
Pages |
37-43 |
Keywords |
Animals; Birds/*physiology; Feeding Behavior/*physiology; Female; *Food; Male; *Memory |
Abstract |
Food caching birds hide food and recover the caches when supplies are less abundant. There is, however, a risk to this strategy because the caches are susceptible to pilfering by others. Corvids use a number of different strategies to reduce possible cache theft. Scrub-jays with previous experience of pilfering other's caches cached worms in two visuospatially distinct caching trays either in private or in the presence of a conspecific. When these storers had cached in private, they subsequently observed both trays out of reach of a conspecific. When these storers had cached in the presence of a conspecific, they subsequently watched the observer pilfering from one of the trays while the other tray was placed in full view, but out of reach. The storers were then allowed to recover the remaining caches 3 h later. Jays cached more worms when they were observed during caching. At the time of recovery, they re-cached more than if they had cached in private, selectively re-caching outside of the trays in sites unbeknown to potential thieves. In addition, after a single pilfering trial, the jays switched their recovery strategy from predominantly checking their caches (i.e. returning to a cache site to see whether the food remained there) to predominantly eating them. Re-caching remained constant across the three trials. These results suggest that scrub-jays use flexible, cognitive caching and recovery strategies to aid in reducing potential future pilfering of caches by conspecifics. |
Address |
Sub-department of Animal Behaviour, University of Cambridge, High Street, CB3 8AA Madingley, Cambs, UK. nje23@cam.ac.uk |
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English |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1435-9448 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
PMID:12827547 |
Approved |
no |
Call Number |
Equine Behaviour @ team @ |
Serial |
2566 |
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Author |
Hampton, R.R.; Shettleworth, S.J. |
Title |
Hippocampus and memory in a food-storing and in a nonstoring bird species |
Type |
Journal Article |
Year |
1996 |
Publication |
Behavioral neuroscience |
Abbreviated Journal |
Behav Neurosci |
Volume |
110 |
Issue |
5 |
Pages |
946-964 |
Keywords |
Animals; Appetitive Behavior/*physiology; Attention/physiology; Birds/*physiology; Brain Mapping; Feeding Behavior/*physiology; Mental Recall/*physiology; Organ Size/physiology; Orientation/*physiology; Retention (Psychology)/physiology; Species Specificity |
Abstract |
Food-storing birds maintain in memory a large and constantly changing catalog of the locations of stored food. The hippocampus of food-storing black-capped chickadees (Parus atricapillus) is proportionally larger than that of nonstoring dark-eyed juncos (Junco hyemalis). Chickadees perform better than do juncos in an operant test of spatial non-matching-to-sample (SNMTS), and chickadees are more resistant to interference in this paradigm. Hippocampal lesions attenuate performance in SNMTS and increase interference. In tests of continuous spatial alternation (CSA), juncos perform better than chickadees. CSA performance also declines following hippocampal lesions. By itself, sensitivity of a given task to hippocampal damage does not predict the direction of memory differences between storing and nonstoring species. |
Address |
Department of Psychology, University of Toronto, Ontario, Canada. robert@ln.nimh.nih.gov |
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English |
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Series Volume |
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Edition |
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ISSN |
0735-7044 |
ISBN |
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Medium |
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Area |
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Conference |
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Notes |
PMID:8918998 |
Approved |
no |
Call Number |
refbase @ user @ |
Serial |
375 |
Permanent link to this record |
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Author |
Shettleworth, S.J. |
Title |
Memory and hippocampal specialization in food-storing birds: challenges for research on comparative cognition |
Type |
Journal Article |
Year |
2003 |
Publication |
Brain, behavior and evolution |
Abbreviated Journal |
Brain Behav Evol |
Volume |
62 |
Issue |
2 |
Pages |
108-116 |
Keywords |
Animals; Birds/*physiology; Cognition/*physiology; Color Perception/physiology; Feeding Behavior/*physiology; Hippocampus/*physiology; Memory/*physiology; Species Specificity |
Abstract |
The three-way association among food-storing behavior, spatial memory, and hippocampal enlargement in some species of birds is widely cited as an example of a new 'cognitive ecology' or 'neuroecology.' Whether this relationship is as strong as it first appears and whether it might be evidence for an adaptive specialization of memory and hippocampus in food-storers have recently been the subject of some controversy [Bolhuis and Macphail, 2001; Macphail and Bolhuis, 2001]. These critiques are based on misconceptions about the nature of adaptive specializations in cognition, misconceptions about the uniformity of results to be expected from applying the comparative method to data from a wide range of species, and a narrow view of what kinds of cognitive adaptations are theoretically interesting. New analyses of why food-storers (black-capped chickadees, Poecile Atricapilla) respond preferentially to spatial over color cues when both are relevant in a memory task show that this reflects a relative superiority of spatial memory as compared to memory for color rather than exceptional spatial attention or spatial discrimination ability. New studies of chickadees from more or less harsh winter climates also support the adaptive specialization hypothesis and suggest that within-species comparisons may be especially valuable for unraveling details of the relationships among ecology, memory, and brain in food-storing species. |
Address |
Department of Psychology, University of Toronto, Toronto, Ont., M5S 3G3, Canada. shettle@psych.utoronto.ca |
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English |
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ISSN |
0006-8977 |
ISBN |
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Notes |
PMID:12937349 |
Approved |
no |
Call Number |
refbase @ user @ |
Serial |
367 |
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Author |
van Heel, M.C.V.; Kroekenstoel, A.M.; van Dierendonck, M.C.; van Weeren, P.R.; Back, W. |
Title |
Uneven feet in a foal may develop as a consequence of lateral grazing behaviour induced by conformational traits |
Type |
Journal Article |
Year |
2006 |
Publication |
Equine veterinary journal |
Abbreviated Journal |
Equine. Vet. J. |
Volume |
38 |
Issue |
7 |
Pages |
646-651 |
Keywords |
Aging/*physiology; Animals; Animals, Newborn/anatomy & histology/growth & development/physiology; Feeding Behavior/*physiology; Female; Forelimb/*anatomy & histology/*physiology; *Horses/anatomy & histology/growth & development/physiology; Male |
Abstract |
REASONS FOR PERFORMING STUDY: Conformational traits are important in breeding, since they may be indicative for performance ability and susceptibility to injuries. OBJECTIVES: To study whether certain desired conformational traits of foals are related to lateralised behaviour while foraging and to the development of uneven feet. METHODS: Twenty-four Warmblood foals, born and raised at the same location, were studied for a year. Foraging behaviour was observed by means of weekly 10 min scan-sampling for 8 h. A preference test (PT) was developed to serve as a standardised tool to determine laterality. The foals were evaluated at age 3, 15, 27 and 55 weeks. The PT and distal limb conformation were used to study the relation between overall body conformation, laterality and the development of uneven feet. Pressure measurements were used to determine the loading patterns under the feet. RESULTS: About 50% of the foals developed a significant preference to protract the same limb systematically while grazing, which resulted in uneven feet and subsequently uneven loading patterns. Foals with relatively long limbs and small heads were predisposed to develop laterality and, consequently unevenness. CONCLUSIONS: Conformational traits may stimulate the development of laterality and therefore indirectly cause uneven feet. |
Address |
Derona Equine Performance Laboratory, Department of Equine Sciences, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 12, NL-3584 CM Utrecht, The Netherlands |
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English |
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Edition |
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ISSN |
0425-1644 |
ISBN |
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Notes |
PMID:17228580 |
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no |
Call Number |
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Serial |
1774 |
Permanent link to this record |
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Author |
Dixon, G.; Green, L.E.; Nicol, C.J. |
Title |
Effect of diet change on the behavior of chicks of an egg-laying strain |
Type |
Journal Article |
Year |
2006 |
Publication |
Journal of applied animal welfare science : JAAWS |
Abbreviated Journal |
J Appl Anim Welf Sci |
Volume |
9 |
Issue |
1 |
Pages |
41-58 |
Keywords |
*Animal Feed; *Animal Nutrition Physiology; Animals; Behavior, Animal/*physiology; Chickens/*physiology; Crowding; Feeding Behavior/*physiology; Female; Food Preferences/physiology; Oviposition; Random Allocation; Taste |
Abstract |
Injurious pecking has serious welfare consequences in flocks of hens kept for egg laying, especially when loose-housed. Frequent diet change is a significant risk for injurious pecking; how the mechanics of diet change influence pecking behavior is unknown. This study investigated the effect of diet change on the behavior of chicks from a laying strain. The study included a 3-week familiarity phase: 18 chick pairs received unflavored feed (Experiment 1); 18 pairs received orange oil-flavored (Experiment 2). All chicks participated in a dietary preference test (P); a diet change (DC); or a control group (C), 6 scenarios. All P chicks preferred unflavored feed. In Experiment 1, DC involved change from unflavored to orange-flavored; Experiment 2, orange- flavored to unflavored. Compared with controls, Experiment 2 DC chicks exhibited few behavioral differences; Experiment 1 DC chicks exhibited increased behavioral event rates on Days 1 and 7. They pecked significantly longer at their environment; by Day 7, they showed significantly more beak activity. There was little evidence of dietary neophobia. Change from more preferred to less preferred feed led to increased activity and redirected pecking behavior. |
Address |
School of Veterinary Science, University of Bristol, England |
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English |
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Edition |
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ISSN |
1088-8705 |
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Notes |
PMID:16649950 |
Approved |
no |
Call Number |
refbase @ user @ |
Serial |
64 |
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Author |
Stoinski, T.S.; Wrate, J.L.; Ure, N.; Whiten, A. |
Title |
Imitative learning by captive western lowland gorillas (Gorilla gorilla gorilla) in a simulated food-processing task |
Type |
Journal Article |
Year |
2001 |
Publication |
Journal of comparative psychology (Washington, D.C. : 1983) |
Abbreviated Journal |
J Comp Psychol |
Volume |
115 |
Issue |
3 |
Pages |
272-281 |
Keywords |
Animals; Behavior, Animal/physiology; *Discrimination Learning; Feeding Behavior/*physiology; Gorilla gorilla; *Imitative Behavior; Social Behavior |
Abstract |
Although field studies have suggested the existence of cultural transmission of foraging techniques in primates, identification of transmission mechanisms has remained elusive. To test experimentally for evidence of imitation in the current study, we exposed gorillas (Gorilla gorilla gorilla) to an artificial fruit foraging task designed by A. Whiten and D. M. Custance (1996). Gorillas (n=6) watched a human model remove a series of 3 defenses around a fruit. Each of the defenses was removed using 1 of 2 alternative techniques. Subsequent video analysis of gorillas' behavior showed a significant tendency to copy the observed technique on 1 of the individual defenses and the direction of removal on another defense. This is the first statistically reliable evidence of imitation in gorillas. Sequence of defense removal was not replicated. The gorillas' responses were most similar to those of chimpanzees. |
Address |
TECHlab, Zoo Atlanta, Georgia 30315, USA. stoinskit@mindspring.com |
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English |
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Edition |
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ISSN |
0735-7036 |
ISBN |
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Notes |
PMID:11594496 |
Approved |
no |
Call Number |
refbase @ user @ |
Serial |
738 |
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