What hid inside the first exoskeletons?
Yan Motta / EyeEm/EyeEm/Getty Images
Many animals couldn’t survive without their exoskeletons.
Insects, spiders, crustaceans, and coral are just some of the creatures that wear their protection on the outside.
These hard structures appear suddenly in the fossil record between 550 to 520 million years ago, when the Cambrian Explosion took place.