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Author Smith, S.; Goldman, L.
Title Color discrimination in horses Type Journal Article
Year (up) 1999 Publication Applied Animal Behaviour Science Abbreviated Journal Appl. Anim. Behav. Sci.
Volume 62 Issue 1 Pages 13-25
Keywords Horses; Vision; Color; Discrimination; Behavior
Abstract Four Arabian horses and one Thoroughbred were presented with a series of two-choice color vs. gray discrimination problems. Testing was done in a stall containing a wall with two translucent panels that were illuminated from behind by light projected through color or gray filters to provide the discriminative stimuli. Horses first learned to push one of the panels in order to receive the food reward behind the positive stimulus in an achromatic light-dark discrimination task, and were then tested on their ability to discriminate between gray and four individual colors: red (617 nm), yellow (581 nm), green (538 nm), and blue (470 nm). The criterion for learning was set at 85% correct responses, and final testing for all color vs. gray discriminations involved grays of varying intensities, making brightness an irrelevant cue. Three subjects were tested with all four colors. Two of those subjects successfully reached the criterion for learning on all four color vs. gray discriminations, while the third reached criterion with red and blue, but performed at chance levels for yellow and green. A fourth horse was only tested with green and yellow, and a fifth only with blue, and both of those horses successfully reached criterion on the discriminations they attempted. With the exception of the one subject's poor performance with yellow and green, there was no significant difference between horses on any of the discrimination tasks, and no significant difference in their performance with different colors. The results suggest that horses have color vision that is at least dichromatic, although partial color-blindness may occur in some individuals.
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Call Number refbase @ user @ Serial 850
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Author Timney, B.; Keil, K.
Title Local and global stereopsis in the horse Type Journal Article
Year (up) 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 Mech L.D.
Title Leadership in Wolf, Canis lupus, Packs. Type Journal Article
Year (up) 2000 Publication Canadian Field-Naturalist Abbreviated Journal Can Field Nat
Volume 114 Issue 2 Pages 259-263
Keywords Wolf, Canis lupus, leadership, behavior, foraging, movements, pup care, provisioning, sociality, reproduction, breeding, Northwest Territories.
Abstract I examine leadership in Wolf (Canis lupus) packs based on published observations and data gathered during summers from 1986 to 1998 studying a free-ranging pack of Wolves on Ellesmere Island that were habituated to my presence. The breeding male tended to initiate activities associated with foraging and travel, and the breeding female to initiate, and predominate in, pup care and protection. However, there was considerable overlap and interaction during these activities such that leadership could be considered a joint function. In packs with multiple breeders, quantitative information about leadership is needed.
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Call Number Equine Behaviour @ team @ Serial 4688
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Author Anderson, C.; Franks, N.R.
Title Teams in animal societies Type Journal Article
Year (up) 2001 Publication Behavioral Ecology Abbreviated Journal Behav. Ecol.
Volume 12 Issue 5 Pages 534-540
Keywords animal societies, cooperation, division of labor, groups, invertebrates, task types, teams, vertebrates
Abstract We review the existence of teams in animal societies. Teams have previously been dismissed in all but a tiny minority of insect societies. “Team” is a term not generally used in studies of vertebrates. We propose a new rigorous definition of a team that may be applied to both vertebrate and invertebrate societies. We reconsider what it means to work as a team or group and suggest that there are many more teams in insect societies than previously thought. A team task requires different subtasks to be performed concurrently for successful completion. There is a division of labor within a team. Contrary to previous reviews of teams in social insects, we do not constrain teams to consist of members of different castes and argue that team members may be interchangeable. Consequently, we suggest that a team is simply the set of individuals that performs a team task. We contrast teams with groups and suggest that a group task requires the simultaneous performance and cooperation of two or more individuals for successful completion. In a group, there is no division of labor--each individual performs the same task. We also contrast vertebrate and invertebrate teams and find that vertebrate teams tend to be associated with hunting and are based on individual recognition. Invertebrate teams occur in societies characterized by a great deal of redundancy, and we predict that teams in insect societies are more likely to be found in large polymorphic (“complex”) societies than in small monomorphic (“simple”) societies.
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Notes 10.1093/beheco/12.5.534 Approved no
Call Number Serial 2070
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Author Saslow, C.A.
Title Understanding the perceptual world of horses Type Journal Article
Year (up) 2002 Publication Applied Animal Behaviour Science Abbreviated Journal Appl. Anim. Behav. Sci.
Volume 78 Issue 2-4 Pages 209-224
Keywords Horse; Perception; Vision; Olfaction; Touch; Hearing; Pain; Training; Psychophysics; Umwelt
Abstract From the viewpoint of experimental psychology, there are two problems with our current knowledge of equine perception. The first is that the behavioral and neurophysiological research in this area has enormous gaps, reflecting that this animal is not a convenient laboratory subject. The second is that the horse, having been a close companion to humans for many millennia, entrenched anecdotal wisdom is often hard to separate from scientific fact. Therefore, any summary at present of equine perception has to be provisional. The horse appears to have developed a visual system particularly sensitive to dim light and movement, it may or may not have a weak form of color vision in part of the retina, it has little binocular overlap, and its best acuity is limited to a restricted horizontal band which is aimed primarily by head/neck movements. However, the total field of view is very large. Overall, as would be expected for a prey animal, horse vision appears to have evolved more for detection of predator approach from any angle than for accurate visual identification of stationary objects, especially those seen at a distance. It is likely that, as for most mammals except the primates, horses rely more heavily on their other senses for forming a view of their world. Equine high-frequency hearing extends far above that of humans, but horses may be less able to localize the point of origin of brief sounds. The horse's capacity for chemoreception and its reliance on chemical information for identification may more closely resemble that of the dog than of the human. Its tactile sensitivity is high, and the ability of its brain and body to regulate pain perception appears to be similar to that found in other mammals. There is room for a great deal of future research in both the area of equine perception and sensory-based cognition, but for the present time persons interacting with this animal should be made aware of the importance of the sounds they make, the movements of their bodies, the way they touch the animal, and the odors they emit or carry on their clothing.
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Call Number refbase @ user @ Serial 400
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Author Hare, B.; Brown, M.; Williamson, C.; Tomasello, M.
Title The domestication of social cognition in dogs Type Journal Article
Year (up) 2002 Publication Science (New York, N.Y.) Abbreviated Journal Science
Volume 298 Issue 5598 Pages 1634-1636
Keywords Animals; *Animals, Domestic; *Behavior, Animal; *Cognition; *Cues; *Dogs; Food; Humans; Memory; Pan troglodytes; *Social Behavior; Species Specificity; Vision; Wolves
Abstract Dogs are more skillful than great apes at a number of tasks in which they must read human communicative signals indicating the location of hidden food. In this study, we found that wolves who were raised by humans do not show these same skills, whereas domestic dog puppies only a few weeks old, even those that have had little human contact, do show these skills. These findings suggest that during the process of domestication, dogs have been selected for a set of social-cognitive abilities that enable them to communicate with humans in unique ways.
Address Department of Anthropology, Harvard University, Cambridge, MA 02138, USA. bhare@fas.harvard.edu
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ISSN 1095-9203 ISBN Medium
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Notes PMID:12446914 Approved no
Call Number refbase @ user @ Serial 595
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Author Garamszegi, L.Z.; Møller, A.P.; Erritzøe, J.
Title Coevolving avian eye size and brain size in relation to prey capture and nocturnality Type Journal Article
Year (up) 2002 Publication Proceedings of the Royal Society of London. Series B: Biological Sciences Abbreviated Journal Proc Roy Soc Lond B Biol Sci
Volume 269 Issue 1494 Pages 961-967
Keywords adaptation; behaviour; brain size; coevolution; eye size; vision
Abstract Behavioural adaptation to ecological conditions can lead to brain size evolution. Structures involved in behavioural visual information processing are expected to coevolve with enlargement of the brain. Because birds are mainly vision–oriented animals, we tested the predictions that adaptation to different foraging constraints can result in eye size evolution, and that species with large eyes have evolved large brains to cope with the increased amount of visual input. Using a comparative approach, we investigated the relationship between eye size and brain size, and the effect of prey capture technique and nocturnality on these traits. After controlling for allometric effects, there was a significant, positive correlation between relative brain size and relative eye size. Variation in relative eye and brain size were significantly and positively related to prey capture technique and nocturnality when a potentially confounding variable, aquatic feeding, was controlled statistically in multiple regression of independent linear contrasts. Applying a less robust, brunching approach, these patterns also emerged, with the exception that relative brain size did not vary with prey capture technique. Our findings suggest that relative eye size and brain size have coevolved in birds in response to nocturnal activity and, at least partly, to capture of mobile prey.
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Notes 10.1098/rspb.2002.1967 Approved no
Call Number Equine Behaviour @ team @ Serial 5452
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Author Hall, C.A.; Cassaday, H.J.; Derrington, A.M.
Title The effect of stimulus height on visual discrimination in horses Type Journal Article
Year (up) 2003 Publication Journal of Animal Science Abbreviated Journal J. Anim Sci.
Volume 81 Issue 7 Pages 1715-1720
Keywords Animals; *Discrimination Learning/physiology; Female; Horses/physiology/*psychology; Male; Orientation; *Photic Stimulation; Vision/*physiology
Abstract This study investigated the effect of stimulus height on the ability of horses to learn a simple visual discrimination task. Eight horses were trained to perform a two-choice, black/white discrimination with stimuli presented at one of two heights: ground level or at a height of 70 cm from the ground. The height at which the stimuli were presented was alternated from one session to the next. All trials within a single session were presented at the same height. The criterion for learning was four consecutive sessions of 70% correct responses. Performance was found to be better when stimuli were presented at ground level with respect to the number of trials taken to reach the criterion (P < 0.05), percentage of correct first choices (P < 0.01), and repeated errors made (P < 0.01). Thus, training horses to carry out tasks of visual discrimination could be enhanced by placing the stimuli on the ground. In addition, the results of the present study suggest that the visual appearance of ground surfaces is an important factor in both horse management and training.
Address School of Land-based Studies, Nottingham Trent University, Brackenhurst College Campus, Southwell, Nottinghamshire, England NG25 0QF. carol.hall@ntu.ac.uk
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ISSN 0021-8812 ISBN Medium
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Notes PMID:12854807 Approved no
Call Number refbase @ user @ Serial 835
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Author Cheung, C.; Akiyama, T.E.; Ward, J.M.; Nicol, C.J.; Feigenbaum, L.; Vinson, C.; Gonzalez, F.J.
Title Diminished hepatocellular proliferation in mice humanized for the nuclear receptor peroxisome proliferator-activated receptor alpha Type Journal Article
Year (up) 2004 Publication Cancer research Abbreviated Journal Cancer Res
Volume 64 Issue 11 Pages 3849-3854
Keywords Animals; Anticholesteremic Agents/pharmacology; Carcinogens/pharmacology; Cell Division; DNA Replication/drug effects; Fatty Acids/metabolism; Hepatocytes/cytology/drug effects/metabolism/*physiology; Humans; Mice; Mice, Transgenic; Oxidation-Reduction; Peroxisome Proliferators/pharmacology; Pyrimidines/pharmacology; Receptors, Cytoplasmic and Nuclear/genetics/*physiology; Species Specificity; Transcription Factors/genetics/*physiology
Abstract Lipid-lowering fibrate drugs function as agonists for the nuclear receptor peroxisome proliferator-activated receptor alpha (PPARalpha). Sustained activation of PPARalpha leads to the development of liver tumors in rats and mice. However, humans appear to be resistant to the induction of peroxisome proliferation and the development of liver cancer by fibrate drugs. The molecular basis of this species difference is not known. To examine the mechanism determining species differences in peroxisome proliferator response between mice and humans, a PPARalpha-humanized mouse line was generated in which the human PPARalpha was expressed in liver under control of the tetracycline responsive regulatory system. The PPARalpha-humanized and wild-type mice responded to treatment with the potent PPARalpha ligand Wy-14643 as revealed by induction of genes encoding peroxisomal and mitochondrial fatty acid metabolizing enzymes and resultant decrease of serum triglycerides. However, surprisingly, only the wild-type mice and not the PPARalpha-humanized mice exhibited hepatocellular proliferation as revealed by elevation of cell cycle control genes, increased incorporation of 5-bromo-2'-deoxyuridine into hepatocyte nuclei, and hepatomegaly. These studies establish that following ligand activation, the PPARalpha-mediated pathways controlling lipid metabolism are independent from those controlling the cell proliferation pathways. These findings also suggest that structural differences between human and mouse PPARalpha are responsible for the differential susceptibility to the development of hepatocarcinomas observed after treatment with fibrates. The PPARalpha-humanized mice should serve as models for use in drug development and human risk assessment and to determine the mechanism of hepatocarcinogenesis of peroxisome proliferators.
Address Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, USA
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ISSN 0008-5472 ISBN Medium
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Notes PMID:15172993 Approved no
Call Number refbase @ user @ Serial 74
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Author Regolin, L.; Marconato, F.; Vallortigara, G.
Title Hemispheric differences in the recognition of partly occluded objects by newly hatched domestic chicks (Gallus gallus) Type Journal Article
Year (up) 2004 Publication Animal Cognition Abbreviated Journal Anim. Cogn.
Volume 7 Issue 3 Pages 162-170
Keywords Animals; Discrimination Learning/physiology; Dominance, Cerebral/*physiology; Female; Form Perception/*physiology; Imprinting (Psychology)/*physiology; Pattern Recognition, Visual/*physiology; Photic Stimulation; Random Allocation; Vision, Monocular/*physiology
Abstract Domestic chicks are capable of perceiving as a whole objects partly concealed by occluders (“amodal completion”). In previous studies chicks were imprinted on a certain configuration and at test they were required to choose between two alternative versions of it. Using the same paradigm we now investigated the presence of hemispheric differences in amodal completion by testing newborn chicks with one eye temporarily patched. Separate groups of newly hatched chicks were imprinted binocularly: (1) on a square partly occluded by a superimposed bar, (2) on a whole or (3) on an amputated version of the square. At test, in monocular conditions, each chick was presented with a free choice between a complete and an amputated square. In the crucial condition 1, chicks tested with only their left eye in use chose the complete square (like binocular chicks would do); right-eyed chicks, in contrast, tended to choose the amputated square. Similar results were obtained in another group of chicks imprinted binocularly onto a cross (either occluded or amputated in its central part) and required to choose between a complete or an amputated cross. Left-eyed and binocular chicks chose the complete cross, whereas right-eyed chicks did not choose the amputated cross significantly more often. These findings suggest that neural structures fed by the left eye (mainly located in the right hemisphere) are, in the chick, more inclined to a “global” analysis of visual scenes, whereas those fed by the right eye seem to be more inclined to a “featural” analysis of visual scenes.
Address Department of General Psychology, University of Padova, Via Venezia 8, 35131, Padova, Italy. lucia.regolin@unipd.it
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ISSN 1435-9448 ISBN Medium
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Notes PMID:15241654 Approved no
Call Number Equine Behaviour @ team @ Serial 2519
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