Eyes that glow in the pitch-black night make for many a scary tale. But why do wolves’ eyes glow in the dark?

Wolves have a special light-reflecting surface right behind their retinas called the tapetum lucidum that helps animals see better in the dark. When light enters the eye, it’s supposed to hit a photoreceptor that transmits the information to the brain. But sometimes the light doesn’t hit the photoreceptor, so the tapetum lucidum acts as a mirror to bounce it back for a second chance. Cool!