This is one impressive fish, a solitary giant with a tall curved dorsal fin much like an orca whale. It’s the largest of the eight or nine species of hammerheads (family Sphyrnidae), which are immediately recognizable because of their flattened T-shaped heads. Some scientists surmise it acts like an airplane wing, providing lift during swimming. Certainly this "cephalofoil" enhances mobility, allowing the shark to make extremely tight turns, and the position of the eyes at the outer edges of the "hammer" likely improves stereoscopic vision.
Though usually not aggressive, the great hammerhead’s size, averaging 10-12 feet (females are larger than males), demands respect and caution from divers and swimmers. Up until recently encounters were hit and miss, but recent expeditions in the Bahamas Islands of the western Atlantic Ocean have proved reliable for winter-time sightings.
The Great Hammerhead feeds on a wide variety of mid-water and bottom fishes, including other elasmobranchs. Most noteworthy is its preference for skates and rays. At night it hunts stingrays, eagle rays, guitarfish and the like, using an amazing technique. Using the side of its hammer, it pins a ray to the bottom, then deftly rotates its head to the side and bites off a large chunk of the prey’s wing. The pin-spin-and-bite attack continues until the skate or ray is consumed.
These dramatic new images of great hammerhead sharks add to our legacy pictures of this enigmatic species. I will be returning to Bimini in the Bahamas in a couple of weeks to spend more time photographing this remarkable shark.