Great hammerhead shark (Sphyrna mokarran)

Identification and anatomy

The great hammerhead can be identified by several features: a large, wide cephalofoil with a nearly straight front edge; a tall, sickle-shaped (falcate) first dorsal fin; and a robust, streamlined body. The cephalofoil supports enhanced sensory organs, including electroreceptive ampullae, which help locate buried or hidden prey. Coloration is typically grey to brown above and lighter on the belly, aiding camouflage in open water.

Range, habitat and behaviour

Found in tropical and warm temperate seas worldwide, the great hammerhead inhabits coastal zones, continental shelves and occasionally deeper waters. Individuals may be solitary or form loose aggregations. They are capable swimmers that move between habitats to forage, and are sometimes sighted near reefs, seagrass beds and sandy flats where prey is abundant.

Diet and reproduction

Great hammerheads are generalist predators that feed primarily on fish, rays and cephalopods. The cephalofoil aids in pinning rays and detecting prey hidden in sediment. Like other hammerheads, they are viviparous, giving birth to live young after internal development. Litters and reproductive timing vary with location and are less well documented than those of some other shark species.

Conservation and human interactions

Populations of the great hammerhead have declined in many regions due to targeted fishing, bycatch and the demand for shark fins. It is regarded as vulnerable to high fishing pressure because of its slow reproductive rate and late maturity. Though potentially dangerous because of its size, it is not typically aggressive toward people; most encounters are avoidable with caution and awareness.

Notable facts and distinctions

• The great hammerhead is the largest known hammerhead species; more information on size and comparisons can be found via species overviews.
• The broader taxonomic group is commonly referred to as hammerhead sharks, a lineage notable for head expansion and enhanced sensory capability.
• Its tall dorsal fin and nearly straight-fronted cephalofoil distinguish it from other hammerheads like the scalloped or bonnethead species.