Animals do not belong in the circus! They are not trained to do those tricks, unless you call routinely abusing an animal training it! Animals are NOT meant for entertainment! Elephants are hit and even stabbed and are kept alone in tiny pens when not performing, big cats like tigers and lions are whipped and kept in small cages!
As they are habited in the nature they should not be forced to show tricks in circus.In this way they start thinking humans to be harmful to them as a result sometimes they get furious and destroy everything what they get infront of them and also kill humans to satisfy their anger.