Whales get a reward when they do what Sea World trainers want them to do. This may be fish to eat or a back scratch. The trainers use hand signals to tell whales what trick to do next. They also use a machine that makes sounds in the water similar to those that whales make. The young whales copy what their mothers do so they can learn tricks very quickly. Whales can even be trained to stay still while some blood is taken from them to study