“Walking” fish may help scientists understand how ancient animals learned to move on land

By Stephen Ornes

Web edition: January 5, 2012

You may not be familiar with the word tetrapod, but you know one when you see it. All tetrapods are vertebrates — animals with backbones — and most move on land. They also have four limbs — or their ancestors did, as in the case of snakes and whales, for example. Reptiles, birds and amphibians all count as tetrapods, as do mammals. You’re a tetrapod.

By studying fossils, scientists know that tetrapods haven’t always roamed Earth. Now, biologists have found evidence that animals were preparing to walk while still living underwater.

Visit the new Science News for Kids website and read the full story and view a fishy 'walker' at: Fins as early legs