Lobsters are large crustaceans that live in the sea. They form the family of Nephropidae, which is sometimes also called Homaridae. People make a lot of money from catching lobsters and selling them to make seafood.

Biology 
Lots of different kinds of animals that live in the sea are called lobsters. When people talk about lobsters, most of the time they mean clawed lobsters. One kind of clawed lobster is the American lobster. Lots of animals that we call lobsters are not actually clawed lobsters. Squat lobsters, spiny lobsters or slipper lobsters, are all different kinds of animal. Some kinds of crayfish which live in fresh water and reef lobsters are very similar to clawed lobsters.

Smaller kinds of lobsters are sometimes called "lobsterettes". Lobsters do not have bones. They have hard shells which protect them. This hard shell is made from a material called chitin. The shell is so hard that lobsters must climb out of them before they can grow bigger. This is called moulting. When lobsters moult they are weak and easy to attack. If they hide for long enough they will grow a new hard shell and the lobster will be bigger. Some lobsters change color when they grow a new shell. Lobsters can grow new parts of their body when they lose them. Every time they moult the body part will get a little bit bigger and stronger until it is back to normal.

Lobsters live in the sea between the shore and the edge of the continental shelf. They live underwater on rocky, sandy, or muddy ground. They usually live alone in cracks or under rocks.

Lobsters usually eat live food like fish, molluscs, other crustaceans, worms, and some plants. Lobsters sometimes scavenge (eat dead plants and animals). Lobsters also eat other lobsters (cannibalism) when they are put together in small spaces where they cannot get out. Lobsters do not usually eat other lobsters in the oceans. People have found lobster skin in the stomachs of some lobsters. This is because lobsters eat the skin they shed when they moult. Lobsters grow all their lives. Some lobsters live for over 100 years, and some become very big. The Guinness World Records says that the largest lobster was from Nova Scotia, Canada and weighed 20.14 kg (44.4 lb).

Lobsters are usually the same on the left and right sides. Lobsters have claws on their front legs, and one claw can be bigger than the other. One reason they are different sizes is because they do different jobs. Big strong claws can grab food, and little sharp claws can cut the food up so they can eat it. When a fisherman catches a lobster, they like to keep them if the claws are big. People like to eat lobsters with big claws because there is more good tasting meat in them. The head end of the lobster is called the cephalon. The middle part of the lobster is called the thorax. These parts of a lobster are stuck together and can not move, so we put the words together and call them both the cephalothorax. The bottom end of the lobster is called the abdomen, where the tail is. At the end of the tail is a fan. Lobsters have long thin body parts called antennae under their eyes which they can move around. Lobsters use these to feel what is near them, and they also help them find food. Lobsters have eyes but they cannot see very well. Lobsters have three pairs of jaws. All legs of a lobster have claws apart from the ones at the back. Only the front two legs have big claws. The little claws on the other legs help pick up food they find and put them in the jaws so the lobster can eat.

Lobsters usually move slowly by walking on the bottom of the sea floor. When they are in danger and need to escape, they swim backwards quickly by bending their tail down and up. The fan on the tail helps them to swim faster. Lobsters can move at a speed of 5 metres every second when they do this.

References

Other websites 

 
 Lobster Liberation 

Decapods
Seafood