When you purchase a lobster tail, it is most likely that it has come from an un-clawed lobster. Spiny lobsters, or rock lobsters, are the main source for lobster tails. They come from both warm and cold water and they have no claws. Instead of claws, they have very hard shells and extremely long antennae. Spiny lobsters are not the only clawless lobsters, though. Actually, there are more than forty species of lobsters that have no claws. Most range from one to five pounds, but they can grow to weigh up to 15 pounds.
Most people think of Maine lobsters when they think of lobster tails. These are the kind with claws that you can find alive in tanks in almost any supermarket. These are not the lobsters that supply lobster tails, though. This is because of the way these lobsters grow; after they reach one pound, the lobster outgrows the tail meat. This means that the bigger the lobster gets the less tail meat it has, which makes the price go up dramatically.
Therefore, lobsters with claws are sold whole for individuals to cook and clawless lobsters are the main source of lobster tails.