As the name implies, all decapods have five pairs of legs. Lobsters and shrimp have similar body structures, possessing large muscular tails that they use to propel themselves backwards through the water away from danger. Crabs, in contrast, have a very small tail that they keep tucked under their bodies. There are two commercially important families of edible lobsters. They live in subtropical and tropical oceans.
Lobsters crawl rather than swim.
In Homarus , the first of the five pairs of walking legs is modified to form the large crusher and ripper claws. The shieldlike shell covering the main portion of the lobster's body is called the carapace. Lobsters have compound eyes that are carried on movable eye stalks. Each eye is made up of approximately 14,000 individual units. Lobsters can detect movement, and they may be able to perceive images.