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Field guide to marine inhabitants - Fishes

Family: Sphyrnidae

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Photo Courtesy of Chad MacFie

Scalloped Hammerhead Shark
Prepared by Jessica K. Tokarz

Sphyrna lewini 
.
Range: The Scalloped Hammerhead resides in coastal temperate and tropical waters. In the western Atlantic Ocean, this species ranges from New Jersey south to Brazil including the Gulf of Mexico and Caribbean Sea. Occurring over continental and insular shelves, Scalloped Hammerhead Sharks have been observed close inshore, at the mouths of estuaries, and off shore at depths of 820ft (275m). During the day, Scalloped Hammerheads are found closer inshore, moving offshore at night to feed.

Similar Species: The Scalloped Hammerhead Sphyrna lewini is similar in appearance to the Great Hammerhead Shark. The head is the easiest distinguishing characteristic between these two species. While the head of both exhibit a curved front edge with a median indentation, the Scalloped Hammerhead Shark’s head is more strongly curved. Additionally, the Scalloped Hammerhead has internarial grooves which are absent in the Great Hammerhead.


Great Hammerhead exhibits a
straighter frontal head form 


Scalloped Hammerhead has
   a more strongly curved head

Identification: Like all hammerheads, the head of the Scalloped Hammerhead Shark is expanded laterally, resembling a hammer. An indentation positioned centrally on the front margin of the broadly arched head is what distinguishes this species from others. Scalloped Hammerhead Sharks are brownish-gray to bronze or olive on the dorsal surface and pale yellow or white along the ventral surface.

Note: Scalloped Hammerhead Sharks can often be found in large schools numbering in the hundreds. However, they are not considered dangerous and are normally not aggressive towards humans. This species feeds primarily on fish, such as sardines, mackerel and herring, and occasionally on Cephalopods, such as squid and octopus. On rare occasions, Scalloped Hammerhead Sharks have also been witnessed feeding on smaller shark species, like the Blacktip Shark.

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