What Are Litter Boxes?
Litter boxes are small, usually plastic containers, filled with a litter of some kind, which cats use to hide their waste. Litter comes in many forms now, including:
Silica gel crystals
Recycled materials, such as newspapers or nut shells
Why Do Cats Use Litter Boxes?
Both in wild and domesticated cats, burying behaviors arise. Cats instinctually know to bury their waste as a protective function for themselves as well as a means of hiding from prey and finding food to survive. Cats bury their waste in dirt, sand - or at home, litter - to hide the scent they leave behind in their waste. They do this to protect themselves and their kitten from potential predators that could use their scent to track them. They also do this to keep their prey from smelling them nearby and thus running away from cats - meaning no dinner for kitty.
This translates at home with litter boxes, despite the lack of prey and predators out there.