How does a human know that a dog can only see in black and white?

Question

Unless the person physically is the dog how do they know what a dog's vision is like? What tests have been done to prove this?

Answer 1

Actually we know that is not true, but dogs ARE color blind, they see in two colors instead of three exactly the same as some color blind people. The difference between a dogs eyes and ours is that a dog has fewer cones (collect color) and more rods (collect light) so a dog sees colors about like a color blind person, and sees at night about like a person using night vision goggles.

We see "VIBGYOR" (Violet, Indigo, Blue, Green, Yellow, Orange, Red)
dogs see "VIBYYYR" (Violet, Indigo, Blue, Yellow, Yellow, Yellow, and Red). The colors Green, Yellow, and Orange all look alike to dogs.
USC school of veterinary medicine did an extencive study (using live dogs that volenteers brought in to be tested) on color identification.
Dogs thave the most trouble identifing a yellow or orange item on a green background.

Answer 2

I think the idea that dogs are colour blind is stupid just listen to dog owners talk and they can tell you their dogs have a favourite colour my dog adores red she has several toys identical except for colour and she always goes for the red ones. Why does a dog go for people wearing certain colours? I dont put much stock in what "scientists" or "experts" say as another study always comes along with contrary information. for example this is taken from a site http://www.friendlessanimals.com/modules.php?name=Dogs-MM&page=Dog.html
"Dogs were thought to be dichromats and thus, by human standards, color blind.1, 2 New research is now being explored that suggests that dogs may actually see some colour, but not to the extent that humans do. It has also been suggested that dogs see in varieties of purple/violet and yellow shades. Because the lenses of dogs' eyes are flatter than humans', they cannot see as much detail; on the other hand, their eyes are more sensitive to light and motion than humans' eyes. Some breeds, particularly the best sighthounds, have a field of vision up to 270° (compared to 100° to 120° for humans), although broad-headed breeds with their eyes set forward have a much narrower field of vision, as low as 180°.1, 2"

Answer 3

It is not true that dogs are completely colorblind. While dogs do not have the same color vision as humans, they are able to tell yellow from blue. Like a human with red-green colorblindness, they are unable to tell the difference between red and green. The reason for this limited range, in both the colorblind human and the dog, is that there are only two kinds of color receptors in the retinas of their eyes. While most humans have three kinds of color cells, with three different receptor molecules sensitive to blue, greenish-yellow, and red, dogs only have receptors for yellow and greenish-blue. Canine eyes also lack another human trait: the fovea, an area especially dense with detail-sensing cells. As a result, their detail vision is not as good as ours. But they make up for this by having much better night vision and greater sensitivity to movement.

Answer 4

That is an old theory. They can see most of the same colors that we do. I think they see less red than we do. When I was a kid, the house behind us had a black lab. The lady had rescued him as a puppy, she found him in the center of a circle of policemen being beaten with baseball bats by the cops. That dog and I were good friends, but one day I was wearing a blue oxford shirt and Sparky growled at me! We were all warned, he will bite if you are wearing blue. The police were in uniform -- blue uniforms. Proves it as far as I'm concerned! Sparky had a great life at that house, btw.

Answer 5

I'm sure dogs can see colours. We had an Irish Setter who HATED yellow vans! He almost got me coshed leaping at a security guard who got out of one at a bank. He was a rescue dog so I've no idea why he reacted like this.

Answer 6

this question has been asked many times and i will tell my story again. we had a dog who did not like water yet he ran straight down my mums garden and into the canal. we were amazed but you see the canal was covered in pond weed and we think it looked green to him the same as the lawn so he kept running straight into the canal.the answer being he was not colour blind.

Answer 7

A human retina is made of rod and cone cells. Rods for black and white and cones for colour. A dog's eye has only rod cells.

Answer 8

Color blindness does not mean seeing in only black and white. It means being unable to see the difference in similar hues and colors.

Answer 9

Interesting question!! I have often wondered this exact same thing!

Sorry I can't answer for you but will definitely be checking back here to see if anyone else knows something about it.

Answer 10

Colour blindness in dog's is not actually true. However they do have a slightly harder time differentiating blues from greens.