Scalloped Hammerhead Shark

The scalloped hammerhead is a remarkable shark with one of the most unusual heads in the ocean. Its head is stretched out wide and flat on both sides, with its eyes at the far ends. The front edge has gentle bumps and dips, a bit like the scalloped edge of a shell, and that is how this shark got its name.

That amazing head is not just for looks. It is packed with hundreds of tiny sensors that can feel the faint signals given off by other animals. This helps the hammerhead find fish and other prey hidden under the sand. The wide shape also spreads the sensors far apart, which helps the shark steer and even feel the Earth's own magnetic field, a little like a built-in compass.

Scalloped hammerheads are graceful swimmers. In the daytime they often come together in big groups called schools, and sometimes hundreds of them circle slowly over the same underwater spot. At night they spread out to hunt for fish, squid, and other sea creatures.

Even though it can grow longer than a car, this shark is calm and shy around people. It usually swims away from divers and is not considered dangerous to swimmers. Watching a school of them glide by is one of the great sights of the ocean.

Sadly, scalloped hammerheads are in real trouble. So many have been caught by people, especially for their fins, that their numbers have dropped very steeply. The worldwide list of threatened species (kept by the IUCN) now marks them as Critically Endangered, which is its most serious warning before a species is lost from the wild. Rules that protect sharks and their pups are helping to give these gentle giants a chance to recover.