What is a fossil?

Maybe you’ve seen a fossil T. rex, or a fossil wooly mammoth. But what exactly IS a fossil? Can a fossil be a plant, or a footprint? Does a fossil have to be a dinosaur? 

From beautiful amber to ancient DNA, the fossil record of Earth stretches back hundreds of millions of years. In this video, Macauley curator Roger Benson explains how a fossil is different from a skeleton, and shows many of the types of fossils that have helped paleontologists to understand the history of life on our planet.