Q: Since dogs and cats are colorblind does that mean I shouldn’t worry what color toys I get for them?
A: That’s just not so! To be sure, dogs see colors. However, the range of these colors is more restricted to those in the yellow portion of the spectrum. They have a harder time distinguishing between red, yellow, green and orange (albeit better in bright light). And they’re less likely to discriminate between hues of grays.
For cats, there’s a debate as to whether blues and grays are the norm, or whether it’s the same yellow-based spectrum dogs see, just with less saturation and richness of color.
Here’s how it works:
All mammals have rods and cones in their retinas (the light sensing lining of the back of our eyes). The rod cells are more sensitive to movement whereas the cones are more sensitive to light. Humans have more cones than dogs and cats, which is how we can detect a broader range of the light spectrum. (Though this is an oversimplification, of course.)
But here’s the thing: Pets don’t need to see as many colors. After all, they’re hunters who are primarily carnivorous. They don’t need to worry so much about mistaking one kind of edible plant for another, for example. As predators, they’re much more concerned about being able to see their prey move on a landscape or in a forest. Contrast is everything.
That’s where those rod cells come in. With more rods, they can perceive objects in the dark better, whether they’re moving or not. Add that feature to the reflective coating in the back of the eye, which amplifies the available light, and you have a recipe for excellent low light vision — something every crepuscular or nocturnal predator needs.
What’s more, cats, in particular, have a greater range of vision. Their globe-like eyes see a 200-degree range whereas ours only see 180.
Humans best pets in the visual acuity arena, however. We can see stationary or slow-moving objects more crisply at a wider array of distances. Which only makes sense. We’re slow and omnivorous, after all.
So next time you hear someone proclaim that dogs don’t care whether their ball is yellow or blue, you can say that, "Hey, they actually might prefer a yellow one since it probably pops more." And yes, your cat probably does prefer the bright red laser pointer to the little mousey things littering your floor.