What colors can dogs see? Blue, yellow and a lot of brown
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Dogs see color. They just get fewer of them than you do: blue and yellow come through clear, and most of the rest turns into brown.
Two cones instead of three
Color vision starts with cone cells at the back of the eye. Most people have three kinds, tuned to short, medium and long wavelengths of light. The brain compares the three signals and gets the full range, from violet to red.
Dogs have two kinds. Animals with two cone types are called dichromats. In 1989, Jay Neitz, Timothy Geist and Gerald Jacobs published a study in which dogs picked the odd light out of three panels. Their choices matched a two-cone system: one cone type most sensitive near 430 nanometers, in the violet-blue, and the other near 555 nanometers, in the yellow-green.
That's the fact. Everything else in this article follows from it.
What that looks like from down there
With two cones, color comes down to one question: is this light more blue or more yellow? So:
- Blue looks blue.
- Yellow looks yellow.
- Red, orange and green all look like versions of one yellow-brown, told apart mostly by how bright they are.
- Pink drifts toward gray.
- Blue-green looks close to gray. The same study found a neutral point near 480 nanometers, where the two cones respond about equally and the color drops out.
The closest human comparison is red-green color blindness, specifically deuteranopia. People with it have the same blue-or-yellow system. That's why dog-vision filters, including the one on our site, are built from models of it.
The black-and-white myth
For a long time people repeated that dogs see in black and white. They don't. Their palette is smaller, not empty. A dog can tell a blue ball from a yellow one without any trouble. What he can't do is tell a red ball from a green lawn by color alone.
What dogs do better than you
Color isn't the whole story, and dogs aren't losing on every count.
- Dim light. Their retinas have more rods, the cells that work when light is low, and a reflective layer behind the retina called the tapetum lucidum. It's why their eyes glow in flash photos. They see better than you at dusk.
- Movement. Dogs are good at picking up motion. A ball in flight is easy.
- Detail. This one they lose. Dogs see less fine detail than you do. A small, still object far away is harder for them than for you.
Put those together and you get a familiar scene. He tracks the ball perfectly while it moves. It lands, stops, and he starts searching.
What this means for a toy
Once a toy stops moving, color is what's left for his eyes to work with. If the toy and the ground land on the same yellow-brown, he's down to brightness, and then to his nose.
- On green grass, a red or orange toy blends in. A blue toy is a different color.
- On dirt, mulch or a dark floor, a yellow toy stands out by brightness as well as color.
That's the idea behind Beeline. We make toys in the two colors he gets in full. You can see the difference on our Why blue & yellow page, where the same photo of a red ball and a blue ball in grass is shown twice: once as you see it, once filtered to approximate dog vision.
The short version
Dogs are dichromats. Blue and yellow come through clear. Red, orange and green run together as brown. Blue-green goes gray. They see color, just not all of it. If you want him to spot a toy, pick one of the two he gets.