The largest hammerhead, averaging 3.5 m (11.5 ft) and reaching 6 m (20 ft), separated from its smaller relatives by a head with a nearly straight front edge and a first dorsal fin that is absurdly tall, narrow and sickle-shaped. A large one in open water is among the most imposing animals a diver can meet.
The head is a tool for one job in particular. Stingrays bury themselves and defend with a barbed spine; this shark finds them by their electrical signature, pins them to the bottom with the flat of its head, and pivots to bite the wings off while the ray is held down. Great hammerheads are regularly found with ray barbs embedded in the head and jaws, apparently without ill effect.
It also swims on its side. Tracking work found these sharks rolled 50 to 90 degrees for most of their travel time, using that oversized dorsal fin as a lifting surface the way the pectoral fins would otherwise be used, which cuts the energy cost of covering distance by around ten percent. For an animal this size, that is a lot of tuna it does not have to catch.
Litters run to 50 pups, which is exceptional for a shark, and none of it is enough. Great hammerheads have among the highest at-vessel mortality of any shark - most die on the line before they are even landed - and the fins are the most valuable in the trade. The species is Critically Endangered.
The species. Sphyrna mokarran (Rüppell 1837) - Arabic name for this fish. ETYFish
- head with a nearly straight front edge, no central notch
- first dorsal fin very tall, narrow and sickle-shaped
- often swims rolled onto its side
- the largest hammerhead, to 6 m
