Dolphins are my favorite animals, partly because of their extra-cute appearances: “friendly smile”, little flippers, and sleek and shiny body. But their intelligence is what amazes me the most. I once watched a video about dolphin training. I remember in one of the training sessions, the trainer asks the dolphin to go grab a ball from a basket, yet there is no ball in that basket. So the dolphin takes back the empty basket with him to show the trainer and presses the “No” button available. In another session, the trainer gestures two dolphins to perform two simple tricks then gestures them to perform the two tricks in one action. The dolphins immediately perform a combination of the two tricks without the trainer teaching them how.