Crustaceans

ocean · arthropods · hard shells · water

Built for water. Most crustaceans live in oceans, rivers, and ponds. They include familiar creatures like crabs, lobsters, and shrimp, plus less well-known ones like barnacles and krill.

Hard outer shells. Crustaceans have exoskeletons, which are shells on the outside of their bodies instead of bones inside. This tough armor protects them and helps them move with their jointed legs.

Family of arthropods. Crustaceans are part of a huge group called arthropods that also includes insects, spiders, and scorpions. They're all related through millions of years of evolution.

Wild size range. Some crustaceans are so tiny you need a microscope to see them, while others like giant crabs can span many feet across with their legs stretched out.

Mouths that chew. All crustaceans have special jaw parts called mandibles that let them bite and chew their food, which is a feature they share with insects.