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Why do whale's and sharks tails move differently?

dolphins.jpgQuestion

Why do fish's and sharks' tails go side-to-side when swimming, but whales and dolphins go up-and-down?
Neil, Bracknell

Answer

** Definitive **
Name: Les, Bexley
Qualification: Big game fisherman
Answer: Whales and dolphins are mammals and therefore their bone structure works in a completely different way to fish. The mammals’ bone structure works in the same way as ours – and we don’t go side-to-side. Plus, whales and dolphins, being mammals need to get up to the surface to breath, while fish don’t.