It is an established fact that cat litter was invented by Mr Ed Löwe in the US in 1948. He was using dried clay for absorbing oil and grease in his work shop. By coincidence he noticed that his cats loved using this material. Litter trays as such had been in use since before WWII when people still used regular sand, saw dust and old paper as absorbing material. Cat litter entered the European market in the late 1960s. Being a luxury product, the total European market was worth no more than several tens of thousands of tons per year.
A litter box, sometimes called a sandbox, litter tray, cat pan, litter pan, or catbox, is an indoor feces and urine collection box for cats, as well as rabbits, ferrets, miniature pigs, small dogs (such as Beagles and Chihuahuas), and other pets that instinctively or through training will make use of such a repository. They are provided for pets that are permitted free roam of a home but who cannot or do not always go outside to relieve themselves. Many owners of these animals prefer not to let them roam outside for fear that they might succumb to outdoor dangers, such as weather, wildlife, or traffic (indoor cats, on average, live ten years longer than outdoor cats). A litter box makes it possible to shelter pets from these risks.
In the wild, cats naturally excrete in soft or sandy soil for easy burial. They use their paws in a backward sweeping motion to cover their feces. To stimulate this instinctive desire, a litter box's bottom is filled typically with an inch (2.5 cm) or more of cat litter. Litter box filler is a loose, granular material that absorbs moisture and odors such as ammonia. Some litter brands contain baking soda to absorb such odors. The litter material also satisfies a cat's instinctive desire to use an easily dug material. The most common material is clay, although recycled paper "pellets" and silica-based "crystal" variants are also used. Sometimes, when an owner wishes to stimulate the cat's natural instincts, natural dirt is used.