Crustaceans are a type of Arthropod. The name may not sound familiar, but you probably know them. You may even have eaten one.
Crustaceans live mostly in the ocean or other waters. Most commonly known crustaceans are the crab, lobster and barnacle.
Crustaceans have a hard, external shell which protects their body. Crustaceans have a head and abdomen. The head has antennae which are part of their sensory system. The abdomen includes the heart, digestive system and reproductive system.
The abdomen also has appendages, such as legs, for crawling and swimming. Many crustaceans also have claws that help with crawling and eating.