Is a dolphin related to a whale?

I just swam a few laps - something I haven't done for a very very very long time... I used to compete in swimming, I coached, and I taught lessons. Well, those were the dolphin days. Now I'm afraid to say I resemble more of a beached whale gasping and panting at the end of the pool. It'll take a while to get the breathing and pacing down again. It feels like I might die trying, but at least I'm trying.
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