Much like their owners, most house pets expend the majority of their energy during the day, reserving nighttime primarily for sleep and dreams. But many animals -- from the familiar owls and bats to the more exotic leopard geckos and sugar gliders -- are innate creatures of the night, whose sight and other senses are far sharper after the sun goes down.
In order to be part of this amazing nocturnal world, an animal must have eyes with very large lenses, which help to capture more available light. From there, a layer of reflective cells bounces the light through the retina, allowing more information to be obtained in the dark. In addition, most nocturnal animals have very acute senses of smell, hearing, and touch -- tools that prove helpful when the animals cannot locate their food through sight alone.