Skip to main content Skip to navigation

If mollusks have such heavy shells to drag around with them, how have they spread all over the ocean? -Michel W.

Dear Michel,

Mollusks, from land snails and slugs to oysters and mussels in the sea, have a few things in common. They have a head. They have a soft middle part that holds their organs. Then, some have a muscle that’s known as a “foot.”

Read More ...

Dr. Universe: What is something a lot of people might not know about sharks?

It’s Shark Week, so I made a visit to my friend Jon Mallatt. He’s a Washington State University biologist who has studied the jaws of ancient sharks.

dru-hero-pose

Jon Mallatt: Some of them, such as tiger sharks, cat sharks, and even great white sharks, have quite large brains—relative to their body weight— and are intelligent. They are not “primitive” animals. The shark relatives, Manta rays and devil rays, have even larger brains than any shark.

Dr. U: How long have sharks been around, anyways?

JM: At least 420 million years and maybe 460. It is hard … » More …

Read More ...