Thursday, December 17, 2009

WHAT DO DOG AND CAT SEE?

Dogs are red-green color blind. They see a brighter and less detailed world when compared to humans. Peripheral vision is better than humans, but distance is not judged quite as well. Dogs excel at night vision and the detection of moving objects.Dogs and cats have vision with a very limited color spectrum. Blue is visible but red, green, and yellow all appear similar.Dogs are better able to detect movement.


Dogs have much better night vision for 2 reasons:


# The have more rods (which enable night vision).
# They have a structure called the Tapetum Lucidum
This is a reflective surface behind the retina that reflects light back through it.
Although it is commonly believed that dogs and cats see only in black and white, recent evidence suggests that animals may have some degree of useful color vision. The perception of color is determined by the presence of cone photoreceptors within the retina. These cone cells function in bright light conditions and comprise approximately 20% of the photoreceptors in the central retina of the dog. In humans, the central retina is 100% cones. Behavioral tests in dogs suggest that they can distinguish red and blue colors but often confuse green and red.

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