What are the differences between whales or dolphins and fish? What is a mammal? How do whales and dolphins breathe? They may all live in water but whales and dolphins are very different to fish. For a start they are warm blooded and have to surface to take a breath. Another big difference is that on a fish, the tail moves from side to side. On a whale or dolphin, the tail goes up and down. Amazing! Find out more about: Whales - https://uk.whales.org/whales-dolphins/whales Dolphins - https://uk.whales.org/whales-dolphins/dolphins Porpoises - https://uk.whales.org/whales-dolphins/porpoises #whales #dolphins #whalesorg