The term “hammerhead” is often used loosely, leading to confusion about whether it refers to a single animal or a group of sharks. “Hammerhead” is the common name for a collection of distinct species, all sharing the unique flattened, T-shaped head structure. The Great Hammerhead is the largest and most recognizable single species within this group. Understanding the relationship between the general group and this specific shark requires looking at the scientific classification.
The Hammerhead Family Tree
All hammerhead species belong to the scientific family Sphyrnidae, a grouping defined by their trademark head shape, known as the cephalofoil. Most of these sharks, including the largest, are classified into the genus Sphyrna. The Great Hammerhead is a distinct species identified by the scientific name Sphyrna mokarran, making it one member of the family. Other well-known species include the Scalloped Hammerhead (Sphyrna lewini) and the Smooth Hammerhead (Sphyrna zygaena). When people refer to the general “hammerhead shark,” they are usually referring to any of the nine species found globally. The Great Hammerhead is considered a separate biological entity with unique characteristics and conservation needs.
Distinguishing Physical Traits
The most obvious difference between the Great Hammerhead and its relatives is its maximum size. While other large species, like the Scalloped Hammerhead, typically grow to lengths of 10 to 14 feet, the Great Hammerhead can reach a maximum length of up to 20 feet (6.1 meters). This makes it the largest hammerhead species, with mature adults commonly measuring between 11 and 15 feet.
The shape of the cephalofoil provides the most reliable way to identify the Great Hammerhead, even when size is not apparent. Its “hammer” is exceptionally wide, with a leading edge that is nearly straight across. This straight edge is marked by a very shallow or absent central notch, distinguishing it from the arched or deeply scalloped heads of other species.
Another defining feature is the sharkâs first dorsal fin, which is noticeably tall, strongly sickle-shaped, and highly recurved. This fin’s height and shape are disproportionately large compared to other hammerhead species. The Great Hammerhead also possesses pelvic fins with a distinctly concave, or curved inward, rear margin.
The body of Sphyrna mokarran is generally more stout than other large hammerheads, with coloration ranging from dark brown to light gray or olive on the dorsal side. These combined physical markers make the Great Hammerhead visually distinct from all other members of the Sphyrnidae family.
Habitat, Diet, and Conservation Status
Great Hammerheads generally prefer warm, tropical, and subtropical waters worldwide, inhabiting coastal areas, continental shelves, and offshore waters down to 300 meters. Unlike the Scalloped Hammerhead, which is famous for forming large migratory schools, the Great Hammerhead tends to be a more solitary predator. This species is also highly migratory, moving toward cooler waters during the summer months.
The diet of the Great Hammerhead is specialized, with a preference for stingrays, which they actively hunt. The shark uses its cephalofoil, which is densely packed with electroreceptors called ampullae of Lorenzini, to detect the electrical signals of rays buried beneath the sand. Observations suggest the shark then uses its wide head to pin the stingray down before consuming it.
The Great Hammerhead faces serious threats, leading to a severe conservation status. Due to its slow reproductive rate and high vulnerability to fishing pressure, it is listed as “Critically Endangered” by the International Union for Conservation of Nature (IUCN). This designation reflects a significant global population decline, often resulting from being targeted for its large, highly valued fins.