Sunday, March 1, 2009
Can My Cat See In The Dark?
Two of the most active times for my cats are early morning and when we go to bed. I know that Simon is playing with his toys, because I hear his distinctive wrooowl after the lights go off. They run like crazy, but I don't hear anyone crashing into stuff. Do they see in the dark?
Cats are crepuscular, which means they are more active during the twilight times, dawn and dusk, which is also the times when mice and other prey are active. Like humans, cat retinas have two types of receptor cells; cones and rods. Cones are sensitive to color, and rods pick up light and dark. Cats have few, if any, cones for red, so they can't detect that color. They also have many more rods than human retinas, so cat eyes can collect more light than we can. Color is not as important at low light, and the increased amount of rods allow the cats to detect movement better as the patterns of light and dark change. Cats also have a layer behind the retina called the tapetum lucidum (Latin for "bright carpet") that reflects light back to the retina. This is what makes cats' eyes glow in headlights or flash photos. Check out Daisy's laser eyes:
Cats can't see in total darkness. But they do have several adaptations that help them see clearly in light much lower than we would need.