Crab on the Beach Coloring Page: Free Printable Sheet

Crabs and Life Along the Shore

A Suit of Armor Called an Exoskeleton

A crab wears its skeleton on the outside. This hard shell, called an exoskeleton, shields the soft body like a suit of armor and gives the legs something to pull against. It is made of a tough material called chitin, the same stuff that covers insects and shrimp.

The trouble with a hard shell is that it cannot stretch, so a growing crab must molt. It splits the old shell, backs out, and hides while a fresh, roomier shell hardens. Just after molting a crab is soft and squishy, which is exactly when hungry gulls and fish come looking.

Sideways Sprinters with Mighty Claws

Crabs are famous for scuttling sideways. Their jointed legs hinge outward, so a quick sideways scramble is faster and smoother than walking forward. Ghost crabs on sandy beaches are some of the speediest, racing along the tideline in a blur.

Those front pincers do heavy work. Crabs use them to snip food, dig burrows, and wave at rivals. Fiddler crabs even have one giant claw the male waves to attract a mate, while a fresh crusher claw can grow back if one is ever lost.

Beachcombers That Eat Almost Anything

Most crabs are scavengers, cleaning the shore by eating dead fish, plants, worms, and scraps that wash up. This tidy appetite makes them the janitors of the beach, keeping sand and tide pools fresh for everyone else.

Crabs breathe with gills, like fish, but many kinds can scurry on land for a while as long as their gills stay damp. That is why you often spot beach crabs far from the waves, ducking into cool wet burrows dug into the sand.

Thousands of Crabs Around the World

There are more than four thousand kinds of crab, from the pea crab barely wider than a fingernail to the Japanese spider crab whose legs can span twelve feet from claw to claw. They live in oceans, rivers, tide pools, and even damp forests.

Every year Christmas Island in the Indian Ocean fills with millions of red crabs marching from the forest to the sea to lay their eggs, a migration so huge that roads close to let them pass. From tiny tide-pool crabs to that giant parade, these armored beachcombers are a favorite of shore explorers everywhere.

Hermit Crabs and Borrowed Homes

Not every crab grows its own shell. Hermit crabs have soft, curled bellies and protect themselves by backing into an empty snail shell they carry everywhere like a mobile home. As a hermit crab grows, it must hunt for a bigger shell and quickly swap houses, tucking its whole body safely inside.

Sometimes a line of hermit crabs will wait politely by size, and when one finds a roomier shell, each crab trades up in turn. This tidy shell-swapping shows how crabs of every kind have clever ways to stay protected, whether they grow armor or simply borrow it from the beach. Some hermit crabs even carry a small sea anemone on their shell, a stinging bodyguard that rides along and helps scare hungry fish away.