A lot of humans think dogs can see ALL the colors we humans see. Not true, folks.
Some humans think dogs see only black and white. Not true also.
In “What Colors Do Dogs See? Find out if dogs see in color or black and white,” book author Beth Finke said in thebark.com that dogs see colors but not the way humans do.
“People can see a rainbow of variations including violet, blue, green, yellow, orange and red. Dogs can only see blue, yellow and some shades of gray,” she said.
To illustrate further, Finke said “Dogs would see a rainbow as dark yellow (sort of brownish), light yellow, gray, light blue and dark blue. Dogs don't see red, purple (violet), or orange as we do. So, while it is established that dogs see shades of yellow, blue and gray, if a dog were to look at a uniform that is red or green it would appear as faded brownish, gray or indistinct.”
How a dog sees
A dog’s eyes is like a camera, she said.
“Light enters through the pupil. The iris, a structure that can expand and contract, controls the amount of light allowed in. Light then passes through the clear cornea and lens, which focus the light on the retina, a light-sensitive layer. The retina contains color-sensitive cones and motion- and light-sensitive rods, all of which convert light into electrical signals. The cones and rods send these signals via the optic nerve to the brain, which constructs an image from them. Dogs have only two types of cones, compared with the three types in human eyes.”
This is why, she said, dogs can only see blue, yellow and some shades of gray.
Cats and colors
Just like dogs, cats can not see all the colors humans do but their world is not entirely black and white. Cats can see a bit of yellow, blue and gray.
“They just may not see the ‘true’ color of an object. They are also less sensitive to changes in brightness, so they don’t have the ability to perceive color in the rich, vibrant tones that we do,” said Lynn Buzhardt, DVM, in “Do Cats See Color? “ in vcahoospitals.com.
The difference between cats and humans
Buzhardt explained that “Color is discerned by the nerve cells in the eye. The retina of the eye has two main types of cells–rods and cones. The ability to differentiate colors is determined by the presence of the special color sensitive cells called ‘cones.’”
“Human and feline eyes have three types of cones that can identify combinations of red, blue, and green. But because humans have 10 times more cones than cats do, they appreciate more color variations. In scientific observations, cats don’t appear to perceive the full range of colors that humans can. Some scientists believe that cats see only blue and gray, while others think they see also see yellow like their canine counterparts,” Buzhardt added.
While cones are responsible for distinguishing colors, rods detect light levels and motion.
Cats have more rods than humans which allow them to see more in low light and to identify moving objects, Buzhardt said.
Aside from color perception, “felines and humans have other visual differences, said Buzhardt.
Cats are more near-sighted than humans. Humans see an object clear from a distance while cats will need to get closer to the object to see it, about 20 feet away.
But cats have other visual advantages. A cat's eyes can see more at the sides.
“Cats have eyes that are set more on the sides of the head, which allows them a broader range of peripheral vision than we have. The trade-off is a smaller range of visual acuity so cats don’t have the depth perception that we do,” Buzhardt said.
“Also, cats have elliptical pupils that dilate to the max, allowing them to capture as much light as possible. They also have reflective cells under the retina which form the tapetum. The tapetum gives cats the “shiny eye” appearance and also improves their ability to see in dim light,” she said.
Their visual accommodations allow cats to survive, Buzhardt said.
“Seeing well in dim light and picking up slight movements in the forest at great distances improve the cat’s hunting ability. These assets also help a cat know when HE is the prey and needs to flee,” she added.
So to help your cat given these facts, you can do the following:
1. Buy only yellow and blue toys so your cat will enjoy them more.
2. Stand directly in front of your cat if you want his/her attention.