It takes about 20 molts over 5-7 years for a lobster to become an adult. Before shedding its old shell, a paper-thin new shell is formed under the old shell. When the old shell is shed, the lobster is then called a new shell lobster. Some people prefer eating new shell lobsters because you don't need any tools to crack them apart, but there is little difference in meat quality. New shell lobsters are usually harvested from July to October.
Most people think there is no difference in tenderness between the meat of small and large lobsters.
However, cooking a lobster for too long can make it tough. Two kinds of lobster-like crustaceans exist in United States waters. The two, from different families, display two major differences. The New England lobster has claws on the first four legs, lacking in the spiny lobster. The spiny lobster has a pair of horns above the eyes, lacking in the true lobster.