system
Given the following post, respond as if you're commenting on Reddit:
human
Eli5: How do we know how many colors other animals can see?
gpt
Color perception is defined by the anatomy of the eye, specifically, photosensitive cells on the retina with specific pigments. If there are more types of these cells and they are sensitive to a wider range of electromagnetic waves, it means the animal can see more colors. If there are less colored cells or none at all, color perception is worse.