Animal Armor

A giant reptile lumbers through a patch of low-growing plants. It swings its head to the side to snatch a mouthful of leaves. The head is covered with flat, bony plates. Sharp triangles stick out from the sides like horns. Spikes also run down the sides of its broad, domed back, which is shingled with bony plates.

This spiky, armored reptile is an ankylosaurus, a dinosaur that lived about 70 million years ago. It was one of the most heavily armored of all dinosaurs. The bony plates in its skin were welded to its skeleton in some places. Even its eyelids contained pads of bone.

Few meat-eating dinosaurs could take on this armored dinosaur, which was as long as a school bus and as heavy as a tank. If a predator did try to sink its teeth into an ankylosaurus’s armored back, the reptile had one more defense. It swung its huge tail at its enemy—a tail that ended in a massive club of fused bone.

Armor was a primary form of defense for prehistoric animals. Today, many animals still use it. Sharp spikes and spines, tough bony plates, shells, and thick skin help protect animals from the teeth, jaws, and claws of predators.