It is a common misconception that dogs and cats can only see the world in black and white. Let’s look at the science behind how we see colours to better explain what your pets can see!
Humans and their furry friend both have two kinds of receptors in their eyes: rods and cones. Rods handle peripheral and night vision – this means shades of grey and brightness. Cones are for colour and vision during the day. Each of the cones can detect a different wavelength of light.
Your pets have a higher concentration of rod receptors and a lower concentration of cone receptors. Humans have the opposite, which why we can’t see as well at night but can see more varieties of colour.
Humans are known as trichromats, meaning they have three kinds of cones that allow them to see red, green, and blue – enough to make up our rainbow! It is thought that cats may also be trichromats, but not in the same way that humans are. They can see shades of blue and green, but reds and pinks can be confusing. Reds may appear more green, and purples might look like shades of blue. Dogs only have two cones and that limits their colour receptors to blue and yellow – Like someone with red-green colourblindness.
So What Can Your Pets See?
Dogs can see blues and yellows in all their shades and brightnesses, but cannot see greens and reds. This means that if your dog looks at something orange, it will see the yellow hues but not the red, making the orange look yellow. Look how these orange Mardi Gras outfits become yellow:
Your cat can see shades of blue and green, but reds and pinks can be confusing. These may appear more green, while purple can look like another shade of blue. Since your cat’s eyes have fewer cones, they also see less saturated colours. Like this:
Can My Pets Really See in the Dark?
You might notice how both the dog and the cat vision are blurrier, this is because they are more nearsighted than most humans. Being able to see close up and being able to see in dimmer light is good for animals that have to hunt small prey like cat’s and dog’s ancestors.
Both dogs and cats have a better ability to see in low light and darkness than humans do. Dogs and cats have evolved to have larger pupils and more rods (light-sensitive cells) in their retinas, they also have a mirror-like structure in the back of their eyes that reflects light called the tapetum. This reflects the light and gives your pet a second chance to register the light that has entered their eye. This is also why your pet’s eyes glow in photos!
Cats ability to see in the dark is slightly better than dogs, cats can see details and shapes with one-sixth of the light that a human would need.
Here’s what your human eye can see vs. what your cat’s eye can see.
You can see that although it is lighter, it is also blurrier. Paul Miller, a clinical professor of comparative ophthalmology at the University of Wisconsin-Madison says that “Although the tapetum improves vision in dim light, it also scatters some light, degrading the dog’s vision from the 20:20 that you and I normally see to about 20:80,”. A cat’s visual ability can range from 20/100 to 20/200, which means a cat has to be at 20 feet to see what an average human can see at 100 or 200 feet.
So What Colour Toys Should I Get My Pets?
Now we know that dogs can’t see reds and greens and the colours they can see most clearly are blues and yellows. If you have a red ball on green grass what does your dog see? More like a yellow ball on a slightly different shade of yellow grass.
Dog’s can distinguish between lights and darks very effectively, so light coloured toys on dark grass or dark toys in light snow will be very easy for your dog to see. Your dog doesn’t know that a toy is pink or red but can tell really clearly if a toy is light blue or bright yellow!
A person’s colour spectrum (top) vs. a dog’s colour spectrum (bottom)
Cat’s can see a fuller spectrum of colours so a toy’s colour won’t matter as much. Your cat’s ability to see colour is really just to help them see movement, their number one hunting tool. So your feline friend will be more attracted to movement rather than colour!