Maine's most popular crustacean is, of course, the American lobster, Homarus americanus. This crustacean has two large claws at the front of its body. The crushing claw, the larger, broader of the two, is used for crushing the shells of prey. The small, narrower claw, known as the pincer claw, is used to rip and shred food material. Unlike crabs, lobsters have an elongated abdomen or tail. The tail is used in locomotion to swim, when contracted forcefully the lobster is forced backward in spurts of movement. The tail on the female is also used to carry and protect developing eggs until they hatch.

The lobster is an important commercial marine organism in the state, holding it's position as the number one fishery for decades. In 2004 alone, over 70 million pounds of lobster were harvested in Maine that had a value of over $285 million.