By David Grimes

The type of lobster you purchase, whether it is a Maine lobster or a rock lobster, will depend greatly on the region of the United States, but also what form you are purchasing your lobster in — as individual tails, as claw meat or as whole lobsters. Maine lobsters are also known as cold water lobsters, and they come from the Northeastern seaboard of the United States and Canada. Rock lobsters, referred to as warm weather or spiny lobsters, come from Florida, California and the Caribbean.

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Rock lobster tails are often flatter and less rounded than Maine lobster tails.

Tail or Claw Meat and Cooking

Maine lobsters are most easily differentiated from rock lobsters by the presence of claws. Rock lobsters do not have any claws, while Maine lobsters have two large claws. Because of this, if you are purchasing only claw or knuckle meat, your lobster meat comes from a Maine lobster. Both Maine and rock lobsters have tail meat, and tail meat from both varieties of lobster can be eaten.

Both Maine and rock lobster tails can be cooked separately, cut from the head or as a whole lobster. Cook both rock and Maine lobster tails whole, halved, butterflied or cut into rounds.

Physical Appearance

In addition to the presence of claws, Maine lobsters have only four additional pairs of legs, while rock lobsters have five pairs. Maine lobsters have much smaller antennae than rock lobsters. The antennae also do not have sharp points, and the shell of the Maine lobster is much smoother. Even the tails of rock lobsters can contain sharp points that can easily prick through skin during preparation. Maine lobsters are darker-colored than rock lobsters, which have a more pronounced red tinge, although both are a mottled blue-green-brown-red color. Rock lobsters have numerous white spots on the hard, outer, rounded shell, and the tails of rock lobsters are generally larger than those of Maine lobsters.

Color, Taste and Texture

The color of cooked lobster meat is similar for both Maine and rock lobsters, turning a rosy red on the outside and an opaque white on the inside. However, Maine lobster meat is much sweeter and firmer than rock lobster meat. With a higher price point, many believe it to be more succulent, a consequence of its colder-water environment, which makes for slow, gradual growth. Rock lobster meat is less sweet and stringier and, in some cases, the meat can be mushy.

Tails or Whole Lobsters

Because they are more expensive than rock lobsters, and because their tails are smaller, Maine lobsters are often sold whole; or as a mix of tail, claw and knuckle meat. You rarely see only the tail meat being sold because of the expense and the size. However, rock lobster, as it contains no meat other than tail meat, is often sold only in tail form. If you are unsure about what type of lobster tail you are being served, look at the hard outer shell for clues — Maine lobster will contain no white or yellow-white spots.