Clawed lobsters should not be confused with spiny lobsters, which have no claws (chelae), and are not closely related. The closest relatives of clawed lobsters are the reef lobster Enoplometopus and the three families of freshwater crayfish.
Lobsters are invertebrates, and have a tough exoskeleton, which protects them. Like all arthropods, lobsters must molt in order to grow, leaving them vulnerable during this time. Lobsters are considered a food delicacy around the world.
Lobsters live on rocky, sandy, or muddy bottoms from the shoreline to beyond the edge of the continental shelf. Lobsters generally live singly in crevices or in burrows under rocks.
Although many studies suggested that lobsters are primarily scavengers, feeding on mollusks and decaying animal matter, recent studies have shown that they primarily feed on live fish, dig for clams, sea urchins, and on algae and eel-grass. Lobsters occasionally eat other lobsters, too. An average grown-up lobster is about 230 mm (9 inches) long and weighs 700 to 900 g (1.5 to 2 pounds). Lobsters grow throughout their lives, though, and are long-lived. Lobsters can thus reach impressive sizes. According to the Guinness World Records, the largest lobster was caught in Nova Scotia, Canada and weighed 20.14 kg (44.4 lb).
Like all arthropods, lobsters are largely bilaterally symmetrical; clawed lobsters often possess unequal, specialized claws, like the stone crab. The anatomy of the lobster includes the cephalothorax which is the head fused with the thorax, both of which are covered by the carapace, and the abdomen. The lobster's head consists of antennae, antennules, mandibles, the first and second maxillae, and the first, second, and third maxillipeds. Because a lobster lives in a murky environment at the bottom of the ocean, its vision is poor and it mostly uses its antennae as sensors. The abdomen of the lobster includes swimmerets and its tail is composed of uropods and the telson.