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Great Hammerhead Shark

The great hammerhead shark is the largest of all hammerhead species, capable of growing up to 6 meters (20 feet) long and weighing over 449 kilograms (990 pounds).  Its iconic hammer-shaped head, or cephalofoil, enhances the shark’s ability to detect prey through specialized sensory organs. 

 

Great hammerheads are found worldwide in tropical, coastal waters. These solitary sharks are known to migrate long distances upwards of 3,000 kilometers (1,864 miles).  They are distinguished from other hammerheads by their broad, nearly straight cephalofoil, which provides enhanced vision and electroreception. This specialized head allows them to detect the faint electrical signals of prey hidden in the sand. Great hammerheads primarily feed on rays, small sharks, squid, and bony fish. They have even been seen using the sides of their heads to pin down their preferred meal, stingrays, while feeding on the ray’s wing. As apex predators, these sharks play a vital role in helping to regulate marine ecosystems. 

Great hammerheads also have a faster growth rate than the other hammerhead species and reach maturity earlier as young as six years old. Great hammerheads mate via internal fertilization and give birth to live young — anywhere from 6 to 42 pups — once every two years. 

 

 

Despite their strength and adaptability, great hammerheads face significant threats from human activity. Their greatest threat is overfishing, as these sharks are both targeted by fishers and caught as bycatch. They are caught by a variety of fisheries, including longlines, gillnets, and sometimes trawls. They are also highly sought after in the global shark fin trade. Due to these pressures, the great hammerhead shark is classified as Critically Endangered by the IUCN Red List.

 

 

Supporting conservation efforts is crucial to protecting great hammerhead sharks. Oceana campaigns to combat the shark fin trade, reduce bycatch, and protect sharks and other species from destructive fishing practices. Following support from Oceana and our allies, the deadly shark fin trade has now been banned in the United States and Canada. You can learn more about our campaign to protect threatened ocean species here. 

 

 

  • Animal Diversity Web 
  • Florida Museum of Natural History 
  • Guttridge, TL, Van Zinnicq Bergmann, MPM, Bolte, C, et al. (n.d.). Philopatry and Regional Connectivity of the Great Hammerhead Shark, Sphyrna mokarran in the U.S. and Bahamas. Frontiers in Marine Science 4. https://doi.org/10.3389/fmars.2017.00003 
  • IUCN Red List 
  • Moncrief-Cox, HE, Hannan, KM, Passerotti, MS, Driggers, WB, and Frazier, BS. (2021) Reproductive parameters of great hammerhead sharks (Sphyrna mokarran) and scalloped hammerhead sharks (Sphyrna lewini) from the western North Atlantic Ocean. SEDAR77-DW18. SEDAR, North Charleston, SC. 1-19p.

 

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