Dogs have dichromatic vision (like red-green colorblind humans). They possess blue-sensitive and yellow-sensitive cones but lack red-sensitive ones. As a result:
- Reds (like the apple) appear as yellowish, brownish, or grayish.
- Greens (grass, trees) appear as yellowish or muted olive/gray.
- Blues (the puppy’s eye, sky) remain relatively clear and stand out.
- Black, white, and gray tones look similar to how we see them.
- The overall world looks less vibrant and more “yellow-blue” tinted.
The edited image above shows the exact same scene through a dog’s eyes. The apple loses its bright red pop and blends into the yellowish-brown range, while the lush green landscape becomes a more subdued yellow-green/gray world. The puppy’s face and blue eye are still very recognizable because those colors fall within a dog’s visible spectrum.
This is why dogs are often more attracted to blue or yellow toys than red or green ones — those colors simply don’t stand out the same way to them!