16/10/2023
Hammerhead sharks derive their name from their distinctive hammer-shaped heads. This unique adaptation enhances their agility, provides a 360° field of vision, and amplifies their ability to sense electrical currents—a sixth sense shared by all sharks.
Sharks possess numerous tiny pores, known as ampullae of Lorenzini, covering their heads and snouts. These pores are remarkably sensitive and can detect even the faintest electrical fields, such as those generated by Earth's geomagnetic field or the muscle contractions of prey. The broad, flat head of a hammerhead shark offers a significantly larger surface area for these pores, making them exceptional at locating buried prey, like stingrays concealed beneath the sand.
The hammerhead shark family comprises nine species, with the Great, Scalloped, and Smooth Hammerheads being the largest. Each exhibits slight variations in the shape of their head, reflected in their names.
The Smooth Hammerhead's head, or cephalophoil, is notably smooth and rounded. In contrast, the Scalloped Hammerhead features wavy indentations resembling a scallop shell, while the largest among them, the Great Hammerhead, boasts a straighter front edge.
The Smooth Hammerhead Shark boasts a global distribution but prefers temperate waters. There have been recorded sightings in British waters, albeit infrequently.
Younger sharks often form extensive schools for migration, heading south in winter and north in summer, whereas older sharks tend to migrate in smaller groups. Males typically reach sexual maturity at around 2.1 meters, while females mature later at 2.7 meters, giving birth to litters of 20-50 pups. Their estimated lifespan is around 20 years.
The primary threat facing Smooth Hammerheads is overfishing. Although not targeted directly, they are highly sought after for their fins. Consequently, if caught unintentionally (bycatch), they are often retained throughout their range. Fortunately, the retention of hammerhead sharks is prohibited in Atlantic high-seas fisheries.
