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Author Harman, A.M.; Moore, S.; Hoskins, R.; Keller, P.
Title (up) Horse vision and an explanation for the visual behaviour originally explained by the 'ramp retina' Type Journal Article
Year 1999 Publication Equine veterinary journal Abbreviated Journal Equine Vet J
Volume 31 Issue 5 Pages 384-390
Keywords Animals; Behavior, Animal; Cell Count; Eye/*anatomy & histology; Ganglia, Sensory/cytology; Horses/*physiology; Refractive Errors/veterinary; Retina/cytology/*physiology; Vision/*physiology; Visual Acuity; Visual Fields
Abstract Here we provide confirmation that the 'ramp retina' of the horse, once thought to result in head rotating visual behaviour, does not exist. We found a 9% variation in axial length of the eye between the streak region and the dorsal periphery. However, the difference was in the opposite direction to that proposed for the 'ramp retina'. Furthermore, acuity in the narrow, intense visual streak in the inferior retina is 16.5 cycles per degree compared with 2.7 cycles per degree in the periphery. Therefore, it is improbable that the horse rotates its head to focus onto the peripheral retina. Rather, the horse rotates the nose up high to observe distant objects because binocular overlap is oriented down the nose, with a blind area directly in front of the forehead.
Address Department of Psychology, University of Western Australia, Nedlands, Australia
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Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0425-1644 ISBN Medium
Area Expedition Conference
Notes PMID:10505953 Approved no
Call Number refbase @ user @ Serial 836
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Author Hanggi, E.B.; Ingersoll, J.F.
Title (up) Lateral vision in horses: A behavioral investigation Type Journal Article
Year 2012 Publication Behavioural Processes Abbreviated Journal Behav. Process.
Volume 91 Issue 1 Pages 70-76
Keywords Lateral vision; Horse; Equine; Stimulus discrimination; Field of view; Peripheral
Abstract This study investigated lateral vision in horses (Equus caballus) for the first time from a behavioral point of view. Three horses were tested using a novel experimental design to determine the range of their lateral and caudolateral vision with respect to stimulus detection and discrimination. Real-life stimuli were presented along a curvilinear wall in one of four different positions (A, B, C, D) and one of two height locations (Top, Bottom) on both sides of the horse. To test for stimulus detection, the correct stimulus was paired against a control; for stimulus discrimination, the correct stimulus was paired against another object. To indicate that the correct stimulus was detected or discriminated, the horses pushed one of two paddles. All horses scored significantly above chance on stimulus detection trials regardless of stimulus position or location. They also accurately discriminated between stimuli when objects appeared in positions A, B, and C for the top or bottom locations; however, they failed to discriminate these stimuli at position D. This study supports physiological descriptions of the equine eye and provides new behavioral data showing that horses can detect the appearance of objects within an almost fully encompassing circle and are able to identify objects within most but not all of their panoramic field of view.
Address
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Language Summary Language Original Title
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Series Volume Series Issue Edition
ISSN 0376-6357 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Equine Behaviour @ team @ Serial 5621
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Author Mech L.D.
Title (up) Leadership in Wolf, Canis lupus, Packs. Type Journal Article
Year 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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Notes Approved no
Call Number Equine Behaviour @ team @ Serial 4688
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Author Kilian, A.; Fersen, L. von; Güntürkün, O.
Title (up) Left hemispheric advantage for numerical abilities in the bottlenose dolphin Type Journal Article
Year 2005 Publication Behavioural Processes Abbreviated Journal Behav. Process.
Volume 68 Issue 2 Pages 179-184
Keywords Bottlenose dolphin; Hemispheric specialization; Monocular vision; Numerical ability
Abstract In a two-choice discrimination paradigm, a bottlenose dolphin discriminated relational dimensions between visual numerosity stimuli under monocular viewing conditions. After prior binocular acquisition of the task, two monocular test series with different number stimuli were conducted. In accordance with recent studies on visual lateralization in the bottlenose dolphin, our results revealed an overall advantage of the right visual field. Due to the complete decussation of the optic nerve fibers, this suggests a specialization of the left hemisphere for analysing relational features between stimuli as required in tests for numerical abilities. These processes are typically right hemisphere-based in other mammals (including humans) and birds. The present data provide further evidence for a general right visual field advantage in bottlenose dolphins for visual information processing. It is thus assumed that dolphins possess a unique functional architecture of their cerebral asymmetries.
Address
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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
ISSN 0376-6357 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Equine Behaviour @ team @ Serial 5366
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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
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 0042-6989 ISBN Medium
Area Expedition Conference
Notes PMID:10343877 Approved yes
Call Number Equine Behaviour @ team @ Serial 3580
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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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Publisher Place of Publication Editor
Language Summary Language Original Title
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Series Volume Series Issue Edition
ISSN ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number refbase @ user @ Serial 844
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Author Adler, L.L.; Adler, H.E.
Title (up) Ontogeny of observational learning in the dog (Canis familiaris) Type Journal Article
Year 1977 Publication Developmental Psychobiology Abbreviated Journal Dev Psychobiol
Volume 10 Issue 3 Pages 267-271
Keywords Animals; Dogs/*physiology; Female; Learning/*physiology; Male; Vision, Ocular/physiology
Abstract A split-litter technique was used to test observational learning in 4 litters of Miniature Dachshund puppies, 21, 28, 38, and 60 days old at the beginning of the experiment. In one side of a duplicate cage, one puppy of a litter, the demonstrator, learned to pull in a food cart on a runner by means of a ribbon, while another puppy, the observer, watched from an adjacent compartment, separated by a wire screen. Observational learning was demonstrated by the saving in time for the 1st trial when the observer was given the same problem to solve. Maturation, particularly the development of visual function and motor coordination, set a lower age limit for the emergence of observational learning.
Address
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Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0012-1630 ISBN Medium
Area Expedition Conference
Notes PMID:863122 Approved no
Call Number Equine Behaviour @ team @ Serial 5186
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Author Bartoš, L.; Bartošová, J.; Starostová, L.
Title (up) Position of the head is not associated with changes in horse vision Type Journal Article
Year 2008 Publication Equine Veterinary Journal Abbreviated Journal
Volume 40 Issue 6 Pages 599-601
Keywords horse; horse vision; head position; pupil rotation
Abstract It has become accepted that the horse cannot see directly in front when the nose is lowered and must therefore rely on the rider. We tested the hypothesis that this conclusion would be correct only if the horse did not adjust the eyeball horizontal axis to changes of the head position. The results of the present study suggest that it is unlikely that horses have limited vision in relation to their head position when driven by the rider, and that the horse maintains the optimal horizontal eyeball position regardless of head position relative to the ground.
Address
Corporate Author Thesis
Publisher Blackwell Publishing Ltd Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2042-3306 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Equine Behaviour @ team @ Serial 5679
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Author Anderson, J.R.
Title (up) Self-recognition in dolphins: credible cetaceans; compromised criteria, controls, and conclusions Type Journal Article
Year 1995 Publication Consciousness and Cognition Abbreviated Journal Conscious Cogn
Volume 4 Issue 2 Pages 239-243
Keywords Animal Communication; Animals; *Awareness; Discrimination Learning; Dolphins/*psychology; Female; Male; Orientation; *Self Concept; Social Behavior; *Television; *Visual Perception
Abstract
Address Laboratoire de Psychophysiologie, CNRS URA 1295, Universite Louis Pasteur, Strasbourg, France
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 1053-8100 ISBN Medium
Area Expedition Conference
Notes PMID:8521263 Approved no
Call Number Equine Behaviour @ team @ Serial 4163
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Author Loveland, K.A.
Title (up) Self-recognition in the bottlenose dolphin: ecological considerations Type Journal Article
Year 1995 Publication Consciousness and Cognition Abbreviated Journal Conscious Cogn
Volume 4 Issue 2 Pages 254-257
Keywords Animals; Attention; *Awareness; Body Image; Dolphins/*psychology; Exploratory Behavior; Female; Male; *Self Concept; *Social Environment; Species Specificity; Television; *Visual Perception
Abstract
Address Department of Psychiatry and Behavioral Sciences, University of Texas Medical School, Houston 77025, USA
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 1053-8100 ISBN Medium
Area Expedition Conference
Notes PMID:8521267 Approved no
Call Number Equine Behaviour @ team @ Serial 4161
Permanent link to this record