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Sphyrna lewini Species ID:
A streamlined shark possessing the typical wide, hammer-shaped head (1) scalloped with deep grooves (2). The pectoral and dorsal fins are slightly rounded and the tail is forked. Scalloped hammerheads have a grey to bronze back and pale underside (3). Males can be distinguished from females by the presence of small, fingerlike projections called ‘claspers’ on the ends of the pelvic fins (4) Maximum Size:
4.3 m (14 ft) Longevity:
Approximately 35 years Status:
Near threatened according to the IUCN endangered species list Scalloped Hammerhead Sharks & People:
Scalloped hammerhead sharks are under heavy fishing pressure by the unregulated shark finning industry. They are not overtly aggressive towards divers, but are still considered dangerous
Found throughout the world’s tropical oceans Coral Reef Zone:
Inhabit the offshore waters of the continental shelf, but can occasionally be found in the fore reef and drop-off zones
Favourite Habitat: Scalloped hammerhead sharks prefer offshore reefs to fringing reefs. However, they are attracted to sharp dropoffs, walls, offshore islands and seamounts (underwater mountains rising up sharply from the seafloor), where they sometimes form large schools Depth Range:
6–50 m (20–160 ft)
A Day in The Life
Dawn: Scalloped hammerhead sharks move from hunting grounds to resting areas
Day: Scalloped hammerhead sharks school near seamounts or other offshore areas where social interactions take place, although they occasionally visit near-shore reefs
Dusk: Hammerheads leave resting areas and move to hunting grounds
Night: Hammerheads actively forage for food
Who Eats Who?
The scalloped hammerhead is a generalist predator and will eat most species of fish, squid, stingray, smaller sharks, and crustaceans. The scalloped hammerhead shark is one of the largest predatory reef fish and is preyed on only occasionally by the larger tiger shark and, in the Pacific, by killer whales (also known as orcas).
Scuba Diver & Snorkeler Best Practices
Carefully select entry and exit points: Carefully select points of entry and exit from the water to avoid damaging the coral reef.