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Name: Cindy E Clenard
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How long ago was it that we learned that dolphins were mammals? And when did we discover that dolphins were small toothed whales?

Hi Cindy, when the first dolphin was studied by a scientist, (and I'm not sure WHEN that was), it was most likely determined that it was a mammal right away, since it has the physical characteristics that all mammals have: a backbone, mammary glands, and lungs to breathe with. And since dolphins have all the same characteristics as large toothed whales have, it was probably also noted that it was a whale as well at this time. When scientists find something that they haven't seen before, they do a lot of reading to make sure that no one else has seen the "something" before either. In their research, scientists usually use a tool called a "dichotomous key", which asks the s scientist questions about the features of the unknown "something", The questions can be answered "yes" or "no", like, "Does the animal have arms?" if you answered "no" for the dolphin, the key asks you other questions, instead, to distinguish the dolphin from other things that also have fins, like fish. Maybe it would ask, "Does the animal have lungs?", which you answer "yes", and then the key might tell you that you are looking at a dolphin instead of a fish. When we learn or discover something new, scientists add that information to the "key" so that when another scientist finds the same thing, he or she will know what to call it. People have known for a long time that dolphins are mammals, so you wouldn't actually find a key telling you that, however, people still use dichotomous keys to identify different kinds of whales since many of them look fairly similar. I hope this helps! Thanks for asking!

Tom F Ihde

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