Curiosity about cats has followed humankind since the days before Egyptian pharaohs treasured them as signs of good fortune. Much more is known today about what makes these graceful critters tick, yet we’re still mesmerized by a cat’s nighttime eyes and find comfort in the mysterious vibration of a gentle purr. Taken individually, the bits and pieces of cat anatomy and behavior are a crazy quilt of Morse code, text messaging and DIY survival tips. Together, they’re a medley of fun facts that add up to a fur-covered package of intrigue. Let’s look at five unusual cat anatomy facts.
5. Eyes That Glow in the Dark
Green, gold, blue or yellow, cats’ eyes are fascinating orbs that gleam in darkness. Think of the famous Cheshire cat, whose eyes and grin taunted Alice in Wonderland. Use a flashlight beam to observe your cat in a darkened room. That spooky shine is visible even in dim light.
Cats’ eyes have pupils that are larger than humans’, and are controlled by a pair of shutter-like ciliary muscles, creating the cat’s distinctive slit-like pupil in bright light. In darkness, light hitting feline eyes is reflected from a mirror-like membrane behind the retina. This structure is called the tapetum lucidum, and is present in the eyes of cats, dogs, some fish and birds, and other nocturnal hunting animals.
When light enters a cat’s eyes, it goes through the retina, where light-sensor cells, called rods and cones, absorb it. Any unabsorbed light reaches the tapetum lucidum and bounces back to the retina, enabling it to take in more light. Animals with the tapetum lucidum have greater night vision because it lets them absorb more light. This is a great help when looking for prey at night. Cats need only about one-sixth of the light humans need to function in the dark.