The frilled shark was discovered in the 19th century by German ichthyologist Ludwig H.P. Döderlein. He brought two specimens capture in the Tokyo Bay with him when he railed to Vienna. There, he describes the sharks in a document that’s lost today. The first preserved description of them comes from Samuel Garman in the 1884 edition of Bulletin of Essex Institute. He wrote about the shark, alluding to its snake-life qualities and noting how disturbing such a creature would be for the general public. When thinking about it, he considered how since this shark was just discovered, it’s now impossible, in his mind, to rule out the possibility that some other “serpent-like monster of the oceans” is waiting to be uncovered. 

Frilled Shark Appearance 

The frilled shark, also known as Chlamydoselachus anguineus, is often referred to as a “living fossil” due to its eery appearance and the shape of its mouth. The shark has an eel-like body that’s dark brown to grey in color and amphistyly, referring to the articulation of the jaws to the head. The specimens analyzed by scientists are around 2 meters or 6.6 feet in length. It has a dorsal fin in addition to pelvic and anal fins. The name comes from the shape of the six pairs of gill slits along the shark’s throat.

Frilled Shark Appearance
A frilled shark. Credit: OpenCage, CC BY-SA 2.5, via Wikimedia Commons

The largest specimen ever discovered was 6.6 foot long female and 5.6 foot long male. 

Their heads are flat and broad with a rounded snout noted for its vertical nostril slits. Their eyes are moderately large and they have a protective third-eyelid. Their teeth are widely spaced with between 19 and 28 in the upper jaw and 21 to 29 in the lower jaw. Due to the nature of their jaws, they’re able to open their mouths and take in prey that’s considerably larger than one might expect. This includes prey that’s larger than they are. The gills filaments are the feature that gives the sharks their name. They have a frilling, fringed appearance. 

Frilled sharks have a short and round pectoral fin, a small dorsal fin, and large pelvic and anal fins. Their underside features folds of skin that are separated by a groove. Their function is as of yet unknown. 

Frilled Shark Diet 

Frilled shakes eat primarily smaller sharks, bony fish, squid (such as the cock-eyed squid and the flying squid). They also eat cephalopods. When hunting, their large jaws are capable of devouring prey whole. This is especially effective when it comes to cephalopods and squid. They don’t have the same strong bite as other sharks. Instead, they have to make do with their relatively weak bite due to the limited leverage of their long jaws. Some scientists have suggested that the frilled shark hunts with its jaw open. The inside of its mouth has an interesting dark and light arrangement, allowing it to lure its prey in. 

Frilled Shark Habitat 

There are two species of frilled shark distributed throughout the Atlantic and Pacific oceans. They are usually found in waters of the outer continental shelf and upper continental slope. They live near the ocean floor and near to biologically productive areas. This means that, like most animals, they live near-constant food sources. They usually swim toward the surface to feed at night. In one of the best-known areas where frilled sharks are spotted, the Surge Bay off the coast of Honshu, Japan, the sakes are usually at the depth of 50–200 m (160–660 ft). That is until the temperature warms and the sharks swim to deeper waters where it’s cooler. 

Frilled shark habitat consists being on the ocean floor
Frilled shark habitat consists being on the ocean floor. © Citron

The sharks can also be found around Norway, France, Ireland, Morocco, Mauritania, and along the Mid-Atlantic Ridge. They are usually solitary creatures and are rarely found with other remembers of their species. More recently the sharks have been spotted off the coast of New England and Georgia in the United States. 

Frilled Shark Reproduction 

The male shark reaches maturity when it is 3.3–3.9 ft long while the female reaches maturity when it is 4.3–4.9 ft long. The mature female shark has two ovaries and a uterus. The baby shark is born from an encapsulated off retained in the mother’s uterus. When the embryo is 6–8 cm or 2.4–3.1 in long the mother shark expels it. It is also at this time that the baby shark’s gills are developed. A litter consists of two to fifteen pups with the average being six. The gestation period can last as long as 3.5 years. 

A frilled shark in the depths of the ocean
A frilled shark in the depths of the ocean. © Citron

Frilled Sharks and Humans 

Unfortunately, frilled sharks can be caught up in a process known as bycatch, where fishermen bring in untented creatures in their large nets. This often happens while the sharks are hunting. They are often caught up in gill nets used in Japan and meant for sea bream and gnomefish. In 2016, the IUCN designated the frilled shark as under near-threat of extinction because of loss of food sources due to commercial overfishing. Today, they are currently classified differently by different countries. The IUCN classifies them as “least concern” and the New Zealand Threat Classification System lists them as “At risk—naturally uncommon,” meaning that they are not easily found. 

Mouth of a frilled shark
Mouth of a frilled shark. Credit: OpenCage

Facts About Frilled Sharks 

  • There are two species of frilled shark distributed throughout the Atlantic and Pacific oceans.
  • Frilled shakes eat primarily smaller sharks, bony fish, squid, and cephalopods. 
  • Their heads are flat and broad with a rounded snout. 
  • The frilled shark was discovered in the 19th century by German ichthyologist Ludwig H.P. Döderlein.
  • It is sometimes referred to as a “living fossil.” 
  • Their bite is relatively weak compared to other sharks. 
  • They live near the ocean floor.