When about three inches long they again migrate to deeper water. There under ledges and in holes they hide by day and feed by night, mostly on carrion, small snails and clams. In response to the season or food availability, they move en masse, often in columns hundreds of yards long, from shallower to deeper water or along the shore. They grow by periodically molting. They cast off their old shell, swell body tissues with seawater and await the protective hardening of the new shell into which they will flesh out.
Growth slows as they age and molting becomes infrequent.
Still, a spiny lobster in Gulf waters can attain a length of 20 inches and weigh over 10 pounds. Other species in other parts of the world grow even larger. Spiny lobsters can crawl forward and sideways but always swim backward with flaps of their powerful tail, a gesture that presents an armored, thorny face to a potential enemy. Those include octopuses, turtles, nurse sharks and rays none of which eat them with melted butter, a la Newberg or cold with mayonnaise like their greatest enemy, man. During the spawning season spiny lobsters are protected by law.