Underwater picture of a frilled shark
Image credit: © Citron / CC BY-SA 3.0

Upon first glance at this serpentine creature, you may wonder if you are looking at an eel. The long, snake-like appearance of the frilled shark (Chlamydoselachus anguineus) is thought to have inspired the tales of huge sea serpents from long ago. But despite its appearance, the frilled shark is certainly a shark. Named for its strange appearance, this creature has unique gills very similar to the frilly collars worn in the Elizabethan Age (think William Shakespeare, for example).

The frilled shark, also known as the lizard shark or the scaffold shark, has several distinct morphological characteristics. Its slender eel-like shape ends in an elongate caudal, or tail, fin without a lower lobe. It has a single, small dorsal fin located towards the end of its tail, and a terminal mouth with a short, blunt snout and long lower jaw. Its large mouth is armed with rows of needle-sharp, three-pronged teeth used for catching squid, fish and smaller sharks. Frilled sharks are a chocolate brown color with six pairs of frilly gill slits (most sharks only have five). The first pair encircles its entire neck, giving it its unique frilled look.

Frilled sharks are slow-moving in deep waters, among the slowest of all shark species. Found mostly on continental shelves and near the shores of large islands, they are occasionally reported in open waters as well. They mostly are benthic, meaning that they can live at depths ranging from 330 to over 4,200 feet (100-1,300 meters). As bottom-dwellers, frilled sharks’ role in their marine ecosystem may be to remove decomposing carcasses.

Reproduction in frilled sharks is not well understood. What scientists do know, however, is that females reproduce all year long and have a gestation period of about one to two years, producing anywhere from two to fifteen pups per litter. There is little information on the parental investment of frilled sharks; however, sharks generally do not take care of their young after birth.

Scientists believe they have an extremely low resilience to exploitation. Since they are deepwater sharks, fishers sometimes keep them as by-catch and use them for meat or fish meal. There are, fortunately, national and regional initiatives aimed at reducing by-catch of deepwater sharks, which would benefit the frilled shark by extension.

Illustrated head of a frilled shark
Illustration of the frilled shark. Image extracted from Internet Archive Book Image’s Flickr. Originally published in The American Museum journal (1917).

Where do frilled sharks live?

Frilled sharks are found all over the world, scattered in temperate to tropical marine waters, including the Atlantic, Indian, and Pacific Oceans. They can live as far north as Norway and extend down to areas of South Africa. This species is also well-known in Japanese waters, feeding for squids.

How big is a frilled shark?

Frilled sharks range in size, usually being somewhere between 3-5 feet (100-150 cm). The longest frilled shark on record was almost 6-and-a-half feet (197 cm)! Female frilled sharks are usually larger than their male counterparts. Their weight is undocumented.

What do frilled sharks eat?

Although the feeding behavior of this shark is not well-observed, scientists have examined the contents of their stomach to discover their food source; it appears that frilled sharks find their prey in caves and crevices. Frilled sharks can open their jaws extremely wide to eat fish, squid, smaller sharks, and rays. Scientists believe that their flexible jaws allow the shark to swallow their prey whole, which is pretty impressive considering that their prey includes creatures that can be up to half of their size!

What are the predators of the frilled sharks?

There are few known predators of frilled sharks, although other sharks are likely candidates. The biggest threat to the frilled shark is human by-catch.