How well do cats really see at night? We know cats are famous for their night vision — they need only one-fifth as much light to see as humans do — for a couple reasons.

Like other mammals that hunt at night, cats have reflective structures, called “tapetum lucidum,” inside their eyes. Even the faintest light is reflected back to the rods and cones. Dogs have this night vision advantage, too. But cats have a second trick: elliptical pupils that open faster, wider and let in even more light than the round pupils of dogs and humans.

There is one disadvantage to the tapetum, technically called a “retroflector.” Interference from reflected light can make the cat’s night vision a little blurry.

– Dr. Larry McDaniel, DVM for the “Purina® Animal Instincts” Podcast Series