The green land shark is one of the largest living species of shark, it's comparable to those of the great white shark. Greenland sharks grow to 6.4 m (21 ft.) and 1,000 kg (2,200 lb.), and possibly up to 7.3 m (24 ft.) and more than 1,400 kg (3,100 lb.). However, most Greenland sharks observed have been around 2.44-4.8 m (8.0-16 ft.) long and weigh up to 400 kg (880 lb.). Males are typically smaller than females. It rivals the Pacific sleeper shark (possibly up to 7 m or 23 ft. long) as the largest species in the family Somniosidae. The Greenland Shark is a thickset species with a short, rounded snout, small eyes, and very small dorsal and pectoral fins. The gill openings are very small for the species great size. Coloration can range from pale creamy-gray to blackish-brown and the body is typically uniform in color, though whitish spots or faint dark streaks are occasionally seen on the back. Due to their cold environments, Greenland Sharks are thought to grow at a very slow rate. There are no reliable data on their life span, but fully grown Greenland sharks have been recaptured 16 years after being tagged. When feeding on large carcasses, the shark employs a rolling motion of its jaw. The teeth of the upper jaw are very thin and pointed, lacking serrations. These upper jaw teeth, numbering from 48 to 52 teeth, act as a anchor while the lower jaw does the cutting. The lower teeth are interlocking and are broad and square, 50 to 52 in count, containing short, smooth cusps that point outward. Teeth in the two halves of the lower jaw are strongly pitched in opposite directions.