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Ask Dr. Universe mammals
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Why are dolphins mammals and not fish? – Evie, 9, Washington

Dear Evie,

As fellow mammals, you and I have a lot in common. It’s easy to see our similarities because humans and cats spend lots of time together. We may even be roommates or family.

But humans and cats don’t usually have dolphin besties. It’s harder to see what we have in common when our bodies and lives are so different.

To better understand mammal life, I talked with my friend Kevin Turner. He teaches marine biology at Washington State University.

“The name mammal comes from the presence of mammary glands,” Turner said. “So, the major characteristic of mammals is that we have mammary glands to produce milk for our offspring.”

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Why do marine mammals have horizontal tails, but fish have vertical tails? – Peyton, 11, Washington

Dear Peyton,

When you think about a whale, you probably picture an enormous sea creature without legs. But what if I told you the first whale had four legs and could walk on land?

I talked about whales and other marine mammals with my friend Kevin Turner. He teaches marine biology at Washington State University.

He told me marine mammals have horizontal tails because they flex their bodies up and down to move. Fish flex their bodies side to side. Scientists think it has to do with the way different animals evolved.

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Do bats have habits? -Elliot 

Dear Elliot,

You are onto something. Quick, to the bat-lab! That’s where I met up with my friend Christine Portfors, a scientist at Washington State University who studies fruit bats.

Portfors explained that while bats don’t quite have habits like humans, they do have behaviors.

Bats are nocturnal. They sleep during the day and wake up in the early evening. The first thing they’ll do when they wake up is fly around and around their caves for a while.

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