Why aren't cats nocturnal?

Nocturnal animals have adapted in various ways to help them see better in the dark. Some species such as owls have evolved bigger eyes and wider pupils. This enables more light to enter the eye. Other animals have eyes composed nearly completely of rods, a type of vision cells. Although they lack color perception, the high number of rods allow their eyes to activate with only a fraction of the light needed for daytime animals. Another adaptation are reflective lenses behind the retina. These cells collect are refocus available light back through the retinas allowing the rods a second chance to use the scarce light. These lenses are also what cause some animals' eyes to "glow" when hit with light at night.