What tricks can dolphins do?

Dolphins, like humans, enjoy playing. Scientists once did an experiment where they rewarded a dolphin every time she performed a new trick. This went well for several days, as the dolphin went through all the tricks she knew how to do - flips, rolls, bouncing a ball, leaping though a hoop, etc. - and then she ran out of tricks. The scientists and dolphin spent the next couple of days under a lot of stress; the dolphin tried every trick again, and the scientist started to feel guilty about keeping back her snack. Then the dolphin suddenly "got it" - she realized that the scientist was rewarding NEW tricks. The dolphin started dreaming up new tricks and performing them, earning reward after reward! So dolphins can do any trick you can imagine, and then some.