Pikaia grew to four centimeters (about an inch and a half) long. It probably swam close to the sea floor, undulating its body from side to side. Scientists are still trying to figure out what it ate and how it made its living.
They were nothing like the plants, animals or any other life forms that we see today. They lived in a soupy mass that would later become our oceans. Until 517 million years ago, all living things were kind of yucky. They were mostly blobs of gooey substances, more like slugs and jellyfish. The first real animal on the Earth was called a Pikaia, which appeared, in the seas. It was very small; only 2 inches long. About 42 million years after other sea creatures evolved. But these creatures had no jaws or teeth.