Thresher Shark Fact Sheet

Appearance:
Typical thresher shark with a very long tail. The upper lobe is about half the entire size of the shark. Small eyes with orbits that do not expand onto dorsal surface of head. Forehead is strongly convex in lateral view. First dorsal fin erect and angular. Pectoral fins are falcate and narrow-tipped.

Coloration:
Dark, metallic shine, ventral surface white extending over pectoral fins bases as a very conspicuous patch.

Distribution:
Worldwide in warm temperate waters. Western Atlantic: New Foundland to Florida, Bahamas, Cuba. Venezuela to Brazil. Eastern Atlantic; Norway to Ivory Coast. Mediterranean. Western Indian Ocean: South Africa, Tanzania, Somalia, Madagascar, Gulf of Aden, Maledives. Western Pacific: Japan, Korea, China, Australia, New Caledonia. Eastern Pacific: British Columbia to Baja California, Panama, Chile. Central Pacific: Hawaiian Islands.

Biology:
Lives in coastal waters over the continental and insular shelves, and epipelagic. Found from the surface down to 360m, with juveniles living in shallow waters. A very active and fast swimmer, can leap out of the water. This species and the other thresher sharks possess an elevated body temperature due to a special blood circulatory system (rete mirabile) that enables them to live in colder waters.

Feeding:
Thresher shark feed primarily on small schooling fishes (such as herrings, sardines) that are herded together with their tails and then stunned or killed with it.

Size:
Average size between 300cm and 500cm (up to 230kg). Maximum total length about 610cm and 450kg.

Reproduction:
Aplacental viviparous (ovoviviparous), with uterine cannibalism. Two pups per litter. The pups are born in open water and show a fast growth. Size at birth between 115cm and 150cm. Males reach sexual maturity at 260cm, females at 350cm.

Similar species:
Bigeye thresher ( Alopias superciliosus ) but that species has much bigger eyes and contours on its head.

Endangerment:
Unknown.

Danger to humans:
Harmless.