One of the most distinctive fish in the ocean. This is a shark that looks like it was designed by someone who had never seen a shark. Its wide, flattened head is shaped like a hammer. Eyes and nostrils sit at each end. This unusual shape gives it exceptional vision. It also provides electroreception for hunting stingrays buried in the sand. The Māori name Mangoopare refers to the broad, sweeping head. Hammerheads are generally shy of humans. But they are vulnerable to overfishing. They grow slowly. They produce few young. A shark with a head that raises questions. The head is flattened and extended sideways. It forms a hammer shape. The eyes and nostrils are at the ends of the hammer. This wide spacing gives the shark exceptional binocular vision. It allows the animal to scan a larger area for prey. The electroreceptors on the head detect faint electrical signals. These signals come from buried stingrays. A head that is also a sensor array. The biology is specialised. The function is precise. The design is effective. It is a predator of the seafloor. It uses its hammer-shaped head to pin stingrays against the sand. It also eats fish, squid and crustaceans. Hunting happens in schools during the day. This behaviour is unusual for sharks. A shark that works in a team. The coordination is surprising. The strategy is collaborative. The result is efficient. Reproduction is ovoviviparous. This means the eggs develop inside the female. They hatch internally. The young are born alive. A litter contains up to 40 pups. This reproductive strategy allows the mother to protect her young. They are safe until they are ready to face the world. The investment is high. The output is limited. The vulnerability is inherent. Overfishing has reduced global populations. It is listed as Vulnerable by the IUCN. In New Zealand, it is a rare visitor. It appears only in the warmest summers. The sighting is exceptional. The presence is temporary. The status is precarious. To see one is to see a shark unlike any other. The warm sea is blue. The hammerhead cruises, head sweeping side to side, scanning the sand for stingrays. It does not know its head is strange. It does not know it is vulnerable. It just hunts. That is what hammerheads do. It carries on in the deep. Unseen. Unvalued by the casual observer. But prized by those who know. It remains in the blue. A testament to the intact ocean. A relic of the wild deep. It waits for the line. Or it does not. The choice is random. The outcome is certain. The shark persists.