Retinal ganglion cell density of the black rhinoceros (Diceros bicornis): Calculating visual resolution

Pettigrew, John D. and Manger, Paul R. (2008) Retinal ganglion cell density of the black rhinoceros (Diceros bicornis): Calculating visual resolution. Visual Neuroscience, 25 2: 215-220. doi:10.1017/S0952523808080498


Author Pettigrew, John D.
Manger, Paul R.
Title Retinal ganglion cell density of the black rhinoceros (Diceros bicornis): Calculating visual resolution
Formatted title
Retinal ganglion cell density of the black rhinoceros (Diceros bicornis): Calculating visual resolution
Journal name Visual Neuroscience   Check publisher's open access policy
ISSN 0952-5238
1469-8714
Publication date 2008-03-01
Sub-type Article (original research)
DOI 10.1017/S0952523808080498
Open Access Status DOI
Volume 25
Issue 2
Start page 215
End page 220
Total pages 6
Editor Laura J. Frishman
Place of publication New York , U.S.A.
Publisher Cambridge University Press
Language eng
Subject C1
920111 Nervous System and Disorders
1109 Neurosciences
Abstract A single right retina from a black rhinoceros was whole mounted, stained and analyzed to determine the visual resolution of the rhinoceros, an animal with reputedly poor eyesight. A range of small (15-microm diameter) to large (100-microm diameter) ganglion cell types was seen across the retina. We observed two regions of high density of retinal ganglion cells at either end of a long, but thin, horizontal streak. The temporal specialization, which receives light from the anterior visual field, exhibited a ganglion cell density of approximately 2000/mm2, while the nasal specialization exhibited a density of approximately 1500/mm2. The retina exhibited a ganglion cell density bias toward the upper half, especially so, the upper temporal quadrant, indicating that the rhinoceros would be processing visual information from the visual field below the anterior horizon for the most part. Our calculations indicate that the rhinoceros has a visual resolution of 6 cycles/degree. While this resolution is one-tenth that of humans (60 cycles/deg) and less than that of the domestic cat (9 cycles/deg), it is comparable to that of the rabbit (6 cycles/deg), and exceeds that seen in a variety of other mammals including seals, dolphins, microbats, and rats. Thus, the reputation of the rhinoceros as a myopic, weakly visual animal is not supported by our observations of the retina. We calculate that the black rhinoceros could readily distinguish a 30 cm wide human at a distance of around 200 m given the appropriate visual background.
Formatted abstract
A single right retina from a black rhinoceros was whole mounted, stained and analyzed to determine the visual resolution of the rhinoceros, an animal with reputedly poor eyesight. A range of small (15-μm diameter) to large (100-μm diameter) ganglion cell types was seen across the retina. We observed two regions of high density of retinal ganglion cells at either end of a long, but thin, horizontal streak. The temporal specialization, which receives light from the anterior visual field, exhibited a ganglion cell density of approximately 2000/mm2, while the nasal specialization exhibited a density of approximately 1500/mm2. The retina exhibited a ganglion cell density bias toward the upper half, especially so, the upper temporal quadrant, indicating that the rhinoceros would be processing visual information from the visual field below the anterior horizon for the most part. Our calculations indicate that the rhinoceros has a visual resolution of 6 cycles/degree. While this resolution is one-tenth that of humans (60 cycles/deg) and less than that of the domestic cat (9 cycles/deg), it is comparable to that of the rabbit (6 cycles/deg), and exceeds that seen in a variety of other mammals including seals, dolphins, microbats, and rats. Thus, the reputation of the rhinoceros as a myopic, weakly visual animal is not supported by our observations of the retina. We calculate that the black rhinoceros could readily distinguish a 30 cm wide human at a distance of around 200 m given the appropriate visual background.
Keyword acuity
Topography
Horse
Cat
Sensitivity
Nucleus
Dolphin
Rats
Bats
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: 2009 Higher Education Research Data Collection
Queensland Brain Institute Publications
 
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Created: Wed, 18 Mar 2009, 20:04:02 EST by Debra McMurtrie on behalf of Queensland Brain Institute