The pale, almost white fur helps to reflect any available light from the moon or stars into the eyes. Lions' eyes have other adaptations that improve their night vision. Their eyes are proportionally larger than in comparable-sized animals and have round pupils which can readily expand to gather more light. The eyes also have a reflective surface behind their retina known as the tapetum lucidum. This thin layer allows light to reflect back into the lion's eye after it' it has already passed through, giving it two chances to collect more light.