Sunday, July 29, 2012

The Eyesight of Dogs

By Jerry Welsh


Dogs are believed to have the eerie ability to see spirits and ghosts. In spite of this ability, vision is said to be the least sensitive sense of a dog. Our four legged friends are noted to have excellent hearing abilities and ultra sensitive noses but vision of dogs is inferior to that of its human friends.

So what kind of vision do dogs have? In spite of the similarity in genetics, dogs' vision is different from humans'. It was once believed that dogs are living in a colorless world as these four legged friends can only see black and white. Studies have proven that dogs can see colors but unlike humans that have trichomatic vision, dogs are noted to have dichromatic vision. This means that unlike humans, dogs cannot see all the colors in the spectrum. It would be impossible to ask dogs what colors they see but it is generally believed that dogs primarily see shades of yellow and blue. Dogs' eyes do not have the cones sensitive to red and orange colors thus Fido and company cannot distinguish the varying shades of these colors.

Dogs may be poor at distinguishing colors but they sure can see better in the dark. Because of the excellent vision dogs can hunt prey and protect the family and the property at night. Dogs can unerringly capture prey even in the dark because of their incredible night vision. Dogs make dependable guards not only because of their alert and protective nature but also because of this night time vision. Dogs have an excellent night vision because they can dilate their pupils more thereby letting in more light.

Dogs have better night vision because they have tapetum lucidum, a layer of reflective cells behind the retina that reflects back the light and allows the dog to detect objects even in dim lights. The wide angle vision and peripheral vision of dogs are more developed. This vision gives the dog the ability to see even the slightest distant movement.

Dogs though find it hard to focus on the shape of object because they are known to have low visual acuity. Although dogs will be able to see movements from afar, the shape will not be distinguished. Objects that are clear to human eyes at seventy five feet will only be seen clearly and distinguished by dogs at 20 feet

Dogs indeed see the world in a different manner. Dogs may not have an accurate color vision and their vision acuity is believed to be much inferior to ours but this kind of vision is well suited to their needs.




About the Author:



No comments:

Post a Comment