Living fossils

Some fossils are almost identical to animals alive today - these are known as living fossils. David Attenborough compares the fossilized crocodile jaw to that of a living crocodile. A 150 million year old dragonfly fossil has the same body plan as a modern dragonfly. And we know what creature lived in a 50 million year old nautilus shell, because pearly nautiluses still swim in the Pacific today.