What is a Frilled Shark?

Mary McMahon
Mary McMahon

The Frilled Shark is a very unusual type of shark which most biologists believe is a primitive remnant of earlier shark species. Superficially resembling an eel, the Frilled Shark has an elongated body with the trademark six gills of a shark and distinctive three pronged teeth. The scientific name of the Frilled Shark is Chlamydoselachus anguineus, and the common name probably originates from the gills, which stick out more than normal gills, resembling a frilled collar.

Frilled sharks sometimes hunt and eat squid.
Frilled sharks sometimes hunt and eat squid.

It is believed that there is only one species in the Chlamydoselachus genus, although there may be additional species. Some biologists have suggested that the African Frilled Shark is actually a species separate from other Frilled Sharks. Reaching up to a length of six feet (two meters), the dull brown Frilled Shark is found in deep waters all over the world, where it lives on squid and other deep water dwelling fish. The Frilled Shark is known to be oviviparous, which means that the female retains the eggs inside her body until they hatch, although the gestation period is not known for certain. Studies off the coast have Japan have suggested that it may be as long as 3 ½ years, making it the longest gestation period of any animal on Earth.

The Frilled Shark has several identifying features in addition to the long, eel like body. The caudal or tail fin has only a vestigial lower lobe, meaning that the upper lobe of the caudal fin is much larger and more clearly defined. The Frilled Shark has a single small dorsal fin, and a larger and much more pronounced anal fin. The design of the fins may allow the Frilled Shark to rapidly propel itself at prey, and the large mouth of the Frilled Shark allows it to eat very large prey animals. Numerous dead specimens have been studied: so far, no Frilled Shark has survived in captivity.

The fossil record suggests that Frilled Sharks have been around for thousands of years: in fact, the Frilled Shark was initially thought to be extinct, until specimens were recovered in Japan during the 19th century. Due to their shy natures and bottom dwelling habits, Frilled Sharks are imperfectly understood. Biologists still argue over the proper taxonomy of the animal, although most biologists do agree that the Frilled Shark is a threatened species, and may be at serious risk of extinction.

The bizarre shape of the Frilled Shark may be the culprit behind “sea serpent” stings, especially off the coast of Japan. Cryptozoologists might be disappointed by this somewhat mundane explanation, but in actuality spotting a Frilled Shark is a cause for celebration, as the deep dwelling sharks rarely come near the surface of the ocean. In addition, Frilled Sharks represent one of the few animal species which has evolved very little over the millennia, and could almost be viewed as an evolutionary throwback. While seeing a mythological beast would be a thing to remember, a Frilled Shark just might be the next best thing.

Mary McMahon
Mary McMahon

Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a wiseGEEK researcher and writer. Mary has a liberal arts degree from Goddard College and spends her free time reading, cooking, and exploring the great outdoors.

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