It’s not every day that humans get a glimpse of the exceedingly rare frilled shark. Yet Reuters reports that a fisherman noticed the sea creature swimming near Awashima Marine Park in Shizuoka, Japan, back in January 2007. Park staff moved swiftly to capture it and told Reuters that the frilled shark, which typically dwells at depths between 600 and 1,000 meters below the surface, rarely swims in such shallow waters, leading them to believe it was sick at time of capture. In fact, this particular female shark died shortly after being placed in the park’s saltwater pool.
Awashima Marine Park officials told Reuters that the frilled shark is "referred to as a 'living fossil' because it is a primitive species that has changed little since prehistoric times," with an ancient-looking appearance that many are apt to associate with the Mesozoic era. In fact, National Geographic notes that scientists have actually attributed a host of sea monster folklore to this scary-looking deep-sea dweller.
The frilled shark has a serpent-like body and a whopping 300 teeth, according to Simon Boag of the South East Trawl Fishing Association, who spoke with the Australian Broadcasting Corporation (ABC) after another frilled shark was captured by fishermen off the coast of Australia in January 2015. However, while this specific creature was ensnared at a depth of 700 meters by trawlers, its appearance in their nets is still quite unusual; Boag said he doesn't know of any other fishermen who have encountered a frilled shark in their travels.
According to Marine Bio, this primitive species can grow as long as 2 meters and gets its name from its six pairs of frilled gills. Yet swimmers need not worry about its intimidating razor-sharp mouth; the frilled shark feeds only on other bottom-dwellers such as squid and bony fish. Even so, with these infrequent appearances, whether in nets or shallow waters, we can assume that most frilled sharks are lurking safely away from us in their habitat near the ocean floor.