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 golden amber to ancient DNA, the fossil record of Earth stretches back hundreds of millions of years (even billions, for the earliest organisms). In this video, the Museum's 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.