Dolphins have become a popular attraction at zoos in recent years. They are more interesting than lions and tigers because they are livelier and perform tricks like circus animals. They are bored if they are asked to do the same trick twice. This is one reason for believing that they are very clever Dolphins are regarded as the friendliest creatures in the sea, and stories of their helping drowning people and sailors have been common since Roman times. We now have proof of their usefulness. In South Africa two dolphins have been trained to help swimmers in difficulties and drive sharks away from the beach. The more we learn about dolphins, the more we realize that they are better organized and their society is more complex than people. They look after other dolphins when they are ill, care for pregnant mothers and protect the weakest in the society as we do.