I'm Dr. Scott, the paleontologist.

During the age of dinosaurs, the Mesozoic Era, while dinosaurs were wandering around on land, those oceans were filled with big marine reptiles.

They weren't dinosaurs, but they were amazing creatures.

There were long-necked plesiosaurs.

It has a little head.

It has large paddles with five-fingered hands, just like you, but instead, those hands are made into paddles for swimming.

It had rocks in its stomach.

We call them gastroliths, and they were used maybe as ballast to help the animal sink down into the water.

In addition, there were these things called mosasaurs, and this is a mosasaur called plotosaurus here behind me.

Plotosaurus lived in California during the end of the Cretaceous times, and these mosasaurs, like plotosaurus, had big heads, short necks, and these long, long bodies, and they probably swam like sharks.

So they're large, marine predators.

They probably fed on fish a lot of the time just like sharks do, as well as squid, and these shelled creatures called ammonites, which are coiled shells a lot like we see in nautilus today.

So imagine, if you could go into a submarine and travel through that Cretaceous sea 70 million years ago, these would be the kinds of creatures you would see swimming all around you.

Now that would be amazing.