Cats have a natural instinct to bury their waste, which is why they instinctively know how to use a litter box. This instinct is triggered by the smell of the litter, which is why it is important to keep the litter box clean and to use a litter that is specifically designed for cats. Additionally, cats may also be drawn to the litter box due to the texture of the litter, as cats prefer to dig in soft, sandy materials.