Great Hammerhead, Sphyrna mokarran (Rüppell, 1837)

Hammerheads possess the largest and most complex brain of all sharks (Mantas and Devil rays have the largest brain of all Elasmobranchs). Large to process a diverse array of sensory information from the lateral line and electrical and magnetic fields.

Hammerhead Sharks have eyes on the ends of the hammer shaped head which give the shark excellent binocular vision. A hammerhead can improve its stereoscopic vision even further by rotating its eyes and sweeping its head from side to side allowing for almost 360o vision.

Smell and taste are extremely important to a shark. The nostrils have highly sensitive membranes which can pick up even the trace of amino acids in the water. Large olfactory organs in the brain process this information and enable the shark to zero in on the source of a scent by swimming up current. They also use their olfactory system to find mates by detecting pheromones and it may even help guide transoceanic migrations and be a navigational aid.

Electrosensing is a most extraordinary shark sense and can detect tiny electric fields given off by living animals, inanimate objects and even water over the earths magnetic fields. Using the special jelly filled sensory organs known as ampullae of Lorenzini, sharks and Hammerheads especially, can detect prey at close quarters (up to 50cm) even when hidden. Hammerheads, with their large broad wing-like heads, have more ampullae than any other group of sharks. This allows them to quickly and accurately locate, prey buried in the sand. A Hammerheads ability to detect electric fields is also used to orientate sharks within the earths magnetic fields, allowing for cross ocean migrations. Smooth Hammerheads, Sphyrna zygaena, use this sense to follow ‘magnetic highways’ along the ocean floor, linking their day time aggregation sites and night time nocturnal feeding sites.