Bigeye Thresher Shark - Alopias superciliosus

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.

WHAT TO LOOK FOR
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.

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

SIZE
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].

HABITAT
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].

DISTRIBUTION
World-wide, oceanic and coastal.

BIOLOGY
Prey - Pelagic fishes.
Reproduction - Ovoviviparous, 2 to 4 pups per litter.

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

STATUS
Highly vulnerable to oceanic fisheries and likely depleted.