Flaring the gills that give the species its name, a frilled shark swims at Japan's Awashima Marine Park on Sunday, January 21, 2007. Sightings of living frilled sharks are rare, because the fish generally remain thousands of feet beneath the water's surface. Spotted by a fisher on January 21, this 5.3-foot (160-centimeter) shark was transferred to the marine park, where it was placed in a seawater pool. "We think it may have come to the surface because it was sick, or else it was weakened because it was in shallow waters," a park official told the Reuters news service. But the truth may never be known, since the "living fossil" died hours after it was caught.
This serpentine specimen may look like a large eel, but its six slitlike gills help mark it as a cousin of the great white, the hammerhead, and other sharks. But this isn't your average fish. Believed to have changed little since prehistoric times, the frilled shark is linked to long-extinct species by its slinky shape and by an upper jaw that is part of its skull. Most living sharks have hinged top jaws.
With a mouthful of three-pointed teeth, the frilled shark may be a fearsome hunter, but it's considered harmless to humans. Those needle-like choppers are better suited to fleshier forms found in the deep sea, such as squid and other sharks.
Right now it's known as a "living fossil." But the frilled shark may be on its way to joining its ancestors. Often accidentally caught and killed in trawlers' nets in Japanese waters, frilled sharks are known to turn up in fertilizer or animal food and occasionally on dinner plates. The World Conservation Union (IUCN) lists the species as near threatened, meaning it "is close to qualifying for or is likely to qualify for a threatened category in the near future."