Cats move around at night, so they must be able to see in the dark. Where humans can nothing at all, cats can still see. A cat’s eye take in the tiniest bit of light. Inside the eye the light is reflected backward and forward. That is the reason that their eyes glow brightly in the dark.

The pupil of cats’ eye change to control the amount of light that enters the eye. They narrow to tiny slits in bright sunlight but widen to large orbs when it is dark. That is why cats see so well in the dark. In addition there is an area behind the retina that reflects light, and that is why cats’ eye appear to glow in the dark.