tag:blogger.com,1999:blog-13923237.post-76386214524445019412007-03-09T22:07:00.001-08:002007-03-09T22:07:46.148-08:00Dogs were thought to be dichromats and thus, by human standards, color blind. It is now known that dogs can't see the color red very well.<br /><br />Different breeds of dogs have different eye shapes and dimensions, and they also have different retina configurations. Dogs with long noses have a "visual streak" which runs across the width of the retina and gives them a very wide field of excellent vision, while those with short noses have an "area centralis" -- a central patch with up to three times the density of nerve endings as the visual streak -- giving them detailed sight much more like a human's.<br /><br />Some breeds, particularly the best sighthounds, have a field of vision up to 270° (compared to 180° for humans), although broad-headed breeds with short noses have a much narrower field of vision, as low as 180°.Snoreply@blogger.com