Skeleton

bones · structure · animals

Three types of skeletons. Some animals like you have an endoskeleton with bones inside your body. Others like beetles have an exoskeleton, a hard shell on the outside. Some animals like worms use a hydroskeleton, where fluid inside their body keeps them firm and flexible.

Built to support. A skeleton is like the frame of a building. It holds up your soft body parts, keeps them in the right shape, and gives muscles something strong to pull against so you can move.

More than just bones. In animals with endoskeletons, organs and muscles attach to the bones. The skeleton works as a team with your muscles to make movement possible.

Armor on the outside. Animals with exoskeletons like ants and crabs wear their skeleton like protective armor on the outside. It keeps them safe and helps them keep their shape, even when they're tiny.