Genus name, Sphyrna, is Greek for “hammer.” There are many theories as to the purpose of the hammer-shaped head of this genus. One proposal is that the lobes enlarge the area for the electro-sensory system this shark uses to find its prey. Considered potentially dangerous to humans. Although relatively few attacks by this species have been recorded, this may be in part due to the difficulty in distinguishing different species of hammerheads. Listed as “Endangered” on the IUCN Red List. This species is sometimes targeted for fishing due to its large fins, which are considered particularly desirable in the fin trade for use in shark fin soup. Also targeted for its meat, liver oil, hides, carcasses (for fishmeal), and for sport. Caught as by-catch during many commercial fishery operations. Adult has no natural predators except for humans. Juvenile may be preyed upon by larger sharks.
  • Size

    Common length for adult female is 15.8-18 feet (4.9-5.5 m); common length for adult male is about 12.1 feet (3.7 m).
  • Diet

    Diet consists primarily of stingrays, other rays and skates.
  • Range

    Most commonly found in shallow water at depths to 328 feet (100 m) but may occasionally be found at depths to 984 feet (300 m).
  • Habitat

    Occurs in warm temperate and tropical seas worldwide.

Physical Characteristics

  • Largest species of hammerhead shark, with the most distinctly hammer-shaped head of this genus.
  • Coloration is dark grey-brown dorsally and lighter grey ventrally.
  • Body is broad and streamlined in shape with tall, curved dorsal fins, and a large, well-developed tail with distinct lobes.
  • Front of the head is nearly straight across and greatly elongated laterally with flattened lobes. Eyes and nostrils are located on the ends of the lobes.
  • Juvenile shark has a more curved hammer.
  • As in many shark species, the female is larger than the male.
  • Common length for adult female is 15.8-18 feet (4.9-5.5 m); common length for adult male is about 12.1 feet (3.7 m).
  • Common length at birth is about 1.6-2.3 feet (50-70 cm).
  • Maximum length recorded was 20 feet (6.1 m).
  • Maximum weight recorded was 991 pounds (449.5 kg).

Diet / Feeding

  • Diet consists primarily of stingrays, other rays and skates.
  • May also consume other sharks, including other hammerhead sharks, bony fish, including groupers and sea catfish, squid and bottom dwelling crustaceans.
  • Commonly feeds by pinning prey down with hammer and biting pieces off.
  • Feeding primarily occurs at dusk.
  • Although stingrays appear to be a preferred prey, this species does not seem to be harmed by the venomous barbs. One shark was found with up to fifty broken stingray or catfish spines stuck in the jaws, throat and sides of the head.

Range / Habitat

  • Occurs in warm temperate and tropical seas worldwide.
  • Highly migratory species. May be found in both inshore and offshore waters. Typically found over the continental shelf, near islands and reefs, and in lagoons.
  • Most commonly found in shallow water at depths to 328 feet (100 m) but may occasionally be found at depths to 984 feet (300 m).

Reproduction & Growth

  • Viviparous species meaning the young is born live.
  • Common litter size of 13-42 pups.
  • Gestation period is about eleven months. Reproduces once every two years.
  • Births usually occur in late spring and summer

Sources

www.fishbase.org

www.iucnredlist.org

www.arkive.org

www.floridamuseum.ufl.edu

Grzimek’s Animal Life Encyclopedia. Thoney, D. A. and Loiselle, P. V.

Sharks and Rays of Australia. Last and Stevens

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