While all cat poop smells the same to us, cats can tell their droppings apart from those of other felines. When a cat poops, their anal glands excrete a liquid onto the droppings that contains a ton of information about their health and such. Dominant cats often prefer to let their poop lie around to signal to others that this territory is theirs, or that they want to claim this area as their territory. More submissive cats will bury their excrement as they don’t want more dominant cats to think that they are looking for a confrontation.
Even though cats are great hunters themselves, they do not want to attract attention from larger predators such as wolves, mountain lions, or coyotes. For a cat that recently gave birth, covering their urine and feces can mean the difference between her litter of kittens being found and eaten by a large predator or not. Even though your cat should be perfectly safe inside your home, cats will still bury their poop under a layer of litter as this behavior is instinctual. After all, better be safe than sorry!
How about big cats?
Big cats are less likely to bury their poop as they are more territorial and don’t have to worry as much about large predators finding them. Some big cats such as lions leave poop out in the open near the edges of their territory to let others know that this ground is theirs.
In more central areas of their territory, they will more likely bury their poop in order not to attract predators when cubs are around.