A large lobster sitting on top of a lobster pot.
A large lobster sitting on top of a lobster pot.
Courtesy: NOAA

American Lobster (Homarus americanus)

Alternate common names: Northern Lobster, Maine Lobster.
Color: Dark reddish brown to olive green along the carapace, lighter orange and white highlights and red and blue accents on the joints of the legs and claws.
Size: Averages 10 to 12 inches total length; older lobsters may exceed 24 inches.
Habitat: Along rocky ledges in shallow near-shore waters of the Bay. Larger lobsters are found in deeper offshore waters.
Seasonal appearance: More common in summer; migrate to deeper waters in the late fall.


The American lobster is a large crustacean with two large, unequal sized claws used for feeding. Swimmerets line the underside of the tail, which fan water around the burrow and help oxygenate water going to the gills. The gender of an American lobster is determined by examining the first pair of swimmerets behind the last pair of walking legs. In females, this pair of swimmerets is soft and feathery, while in the males they are larger and more rigid. The tail of the female is much broader for carrying eggs.

Life History and Behavior

American lobsters are scavengers as well as predators, eating just about anything they can find along the bottom of the ocean, including fish, small crustaceans, and mollusks. They are cannibalistic as well and have been known to devour other American lobsters in lobster traps. Their cutting claw has sharp teeth used for tearing prey into smaller pieces, while the heavy crushing claw is used to break the shells of mollusks. Smaller claws on the first two pairs of legs are used to direct food into the mouth and to sift through the mud. The last two pairs of legs are used for walking. Although American lobsters walk rather than swim, they can quickly escape a predator with a flap of the tail, scuttling backward with a quick burst of speed. They are aggressive when fighting over territories and can inflict a painful pinch if aggravated. American lobsters are nocturnal and have highly developed sense organs on their legs to detect food in the absence of light.

Fishery Note The Atlantic States Marine Fisheries Commission manages the American lobster fishery to address the conservation and management needs of coastal populations.

Special Notes

Adapted from The Uncommon Guide to Common Life on Narragansett Bay. Save The Bay, 1998.