During the last two centuries, and until recently, the modern circus used many kinds of animals. There were wild animals such as lions, tigers or bears. There may also have been camels, horses, elephants, sea lions and domestic animals such as dogs. In recent years people have changed their ideas. They think that it is unkind to make wild animals perform tricks that are unnatural to them. Many of their trainers used cruel methods to teach these animals to do tricks, e.g. hitting the animals, giving them electric shocks or causing pain in other ways. The animals were always touring around, living in tiny cages. Many countries now do not want to see wild animals in circuses.