the blue shark has a slim, smooth-looking body with large eyes, and a long, cone-shaped snout that is longer than the width of its mouth. it has extremely long, pointed pectoral fins. the dorsal fin is moderate in size. it is closer to the pelvic fins than to the pectoral fins. the blue shark's name comes from its distinct dark blue dorsal surface, and bright blue sides. the belly is white. the colours of the blue shark help it to camouflage in the open ocean. the largest blue shark on record measured 3.8 metres (12.5 feet), but they are rumored to get as large as 6.1 metres (20 feet). males reach maturity at the ages of 4–5 years, when they are at the lengths of between 1.8-2.8 metres (6-9.2 feet). females mature at slightly older ages from 5–6 years, when they are at the lengths of between 2.2-3.2 metres (7.2-10.5 feet). the largest blue sharks range in weights from 204–206 kg (450-454 pounds).