Invertebrates 10. Crabs and Lobster

Crabs belong to a group of water animals called crustaceans Vocabulary: crustaceans An invertebrate water animal with a shell

They also have segmented bodies Vocabulary: Segmented bodies A body made of separate parts that are joined together

Most crabs have five (5) pairs of jointed legs A jointed leg has several separate parts joined together

Four pairs of legs are used for walking on rocks and on land Although crabs can move in any direction, they usually move sideways

The fifth and back pair of legs are used for swimming These legs are often flat like paddles

The two front legs have claws. Crabs use their claws for catching food and for fighting enemies

To shed, or get rid of, a shell and to grow a new one As a crab grows, it molts Vocabulary: molts To shed, or get rid of, a shell and to grow a new one

At the time a crab molts, it can also grow a new leg or class if it has lost one In fact, if some enemy is holding on to a crab’s leg, the crab can separate itself from the leg

Then when the crab molts again, it grows a brand-new leg!

There are many different kinds of crabs. Most crabs live in oceans, but some live in fresh water

The hermit crab can be a marine species or a land species Video of Hermit Crab changing shells Hermit crabs “borrow” shells from other organisms

The pea crab is so tiny that it lives inside the shell of an oyster The giant spider crab of Japan has legs that are 4 feet long

The horseshoe crab lives in the shallow ocean waters with the seahorse

Crabs eat other small crustaceans and plant life In turn, crabs are eaten by many vertebrate animals, like people!

Lobsters belong to the crustacean group of animals Lobsters are found only in salt water

The segmented body of a lobster is divided into 21 segments A lobster has 5 pairs of jointed legs

Four pairs of legs are used for crawling along the ocean bottom Migration of the lobster The other two legs end in large claws, one slightly bigger than the other

A lobster uses its claws to catch and tear apart small fish and mollusks that it eats

Like crabs, lobsters molt Lobsters can also grow a new leg if one breaks off

A lobster’s eyes are on stems that stick out from its head A lobster cannot move its head, but it can move the stems

A lobster has 20 pairs of gills With its gills, the lobster gets the oxygen it needs from the water

This is the kind of lobster that many Americans eat The American lobster is dark green on top and orange or blue underneath This is the kind of lobster that many Americans eat

Today, laws protect lobsters At one time, so many lobsters were being caught that they became endangered Today, laws protect lobsters

March of the Lobster