Sharks are a group of elasmobranch fish characterized by a cartilaginous skeleton, five to seven gill slits on the sides of the head, and pectoral fins that are not fused to the head. Modern sharks are classified within the clade Selachimorpha (or Selachii) and are the sister group to the rays.
Sharks normally can live for more than 50 years average, However The Greenland shark has the longest known lifespan of all vertebrate species (estimated to be between 250 and 500 years) .
The Greenland shark is one of the largest living species of shark. It usually grows 6.4 m (21 ft) long and weighs 1,000 kg (2,200 lb) and possibly up to 7.3 m (24 ft) and more than 1,400 kg (3,100 lb). Most Greenland sharks observed have been around 2.44–4.8 m (8.0–15.7 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.
