It’s a myth that cats and dogs can see in the pitch dark. Like all animals, some light is required for the eye to function properly. Their eyes have a high density of rods, which are the cells that are sensitive to dim light. This means they can see normally with as little as 15% of light required by humans. Their pupils function much as the aperture for a camera does, dilating significantly when they need to take in extra light. Cats, in particular, have exceptionally large pupils and outstanding night-time vision.