With all the hoo-has about white tigers, let me share a short pourquoi about why cats bury their droppings. This story was told by Grandma ages ago and coincidentally mum reminded me about it yesterday when we were talking about the incident at the zoo.
So long long ago, the tiger and the domestic cat were family. According to the tradition, the cat was the uncle of the tiger despite his lack of size. One day, it was the cat's turn to find food for the both of them. His search ended when he encountered a village. There, he was showered with food from the villages and soon he forgot about the tiger. He never went back. The tiger waited and waited and he grew angry as the days passed. Then he made a vow and promised that he and his future descendants will not have mercy and will eat the cat the next time they met. Knowing of this vow, the cat began to hide his trail and will bury his droppings each time.
The end. :)