Just imagine how cat learn to dig...

yes, that makes me think... like we humans our children learn from parents, they tend to watch and learn, so they do what their parents do. In cats perhaps it works the same, kittens are attached to their parents and they see how their parents do the digging and when they are old enough to do it they just do the same. Watch your kittens closely?

its in their nature to bury their pee or poop. cats are naturally clean animals and take most of their waking time grooming themselves. though some cats hate water, there are some cats that you can train and bathe them regularly. my brother who has a friend who owns siamese cats give these cats a bath every week. and sometimes when its summer and its too hot, the cat goes to the bathroom and tries to give itself a bath by plunging into a pail of water!

I agree maybe thats beside from their parents, it also might from nature feeling. They abl to do it by Ur self ^^