Bigeye thresher shark - Alopias superciliosus


Illustration © Marc Dando

Thresher sharks are readily identifiable by their extremely long whip-like tails — tails as long as their bodies. There are three species of thresher sharks: the thresher shark, Alopias vulpinus; the pelagic thresher shark, Alopias pelagicus; and the bigeye thresher, described here.

Long curving, upper tail lobe nearly as long as the rest of the shark. Huge eyes extend onto almost flat-topped head. Deep horizontal groove above gills. Very long narrow pectoral fins, large pectoral fins.

Purplish-grey or grey-brown above, light grey to white below.

At birth, the shark is 3.3 to 4.6 ft [100 to 140 cm] in length. Males mature at about 9.8 ft [300 cm] in length, and females mature at about 9.8-11.5 ft [300-350 cm]. Their maximum length can be greater than 15.1 ft [460 cm].

These sharks frequent tropical and temperate seas, close inshore to open ocean. They range from the surface to over 1640.4 ft [500 m] deep, but mostly between the surface and 328.1 ft [100 m].

World-wide, oceanic and coastal.


  • Prey – Pelagic fishes.

  • Reproduction – Ovoviviparous, 2 to 4 pups per litter.

Uses its tail to stun pelagic fishes on which it feeds.

Highly vulnerable to oceanic fisheries and likely depleted. In 2016, all three species of Thresher sharks (bigeye, common, and pelagic thresher sharks) were placed on CITES Appendix II.