Shellfish are small animals that live inside shells. Their hard shells help to keep them safe from being eaten by other animals or smashed by waves. When shellfish are out of water, their shells stop them from drying out.
These shellfish live in one shell.
Some shellfish live in one shell. The animal that lives inside has a very strong, muscular foot which it uses to move itself and to cling to rocks with. If the animal is in danger, it withdraws and hides inside its shell. These shellfish feed on seaweed or on other animals.
This shellfish has two shells joined together.
Some shellfish have two shells that are hinged together. Scallop shellfish swim by flapping their shells open and shut. Shellfish with two shells feed by sucking in water, and straining out small bits of food.
This hermit crab lives in an old shell.
Hermit crabs have a long soft body which they protect by living in an empty shell. They have a pair of strong hooks on their rear end to hold them safely in their shell. When a hermit crab grows too big for its shell, it will find a bigger shell to live in.