Roger Weller, geology instructor
Photograph taken from National Geographics
The Frilled Shark is one of the few ‘living fossils’ that mankind has found
still alive and active in the world today despite originating in the Late
Cretaceous Epoch, specifically the Campanian period. As one can see from the
picture the Frilled Shark gets its name from the ‘frilled’ nature of its gills,
puffed out in the picture above.
Photograph taken from National Geographic
It has a vaguely eel-like shape with few of the features we commonly associate
with sharks. The dorsal fin is a long and ridge like, very different from the
usual triangular dorsal we‘re so used to seeing. The pectoral fins are of an
unusual shape, broader, more like spades or paddles than the cut sharp-looking
standard. The tail, instead of being the broad, creased fin we see so often is
instead a billowy trailing mass akin to that of a Siamese Fighting Fish or, as
previously mentioned, an eel. Most interestingly the Frilled Shark’s teeth are
absolutely one of its most unique features.
As we can see here it has a unique almost shell-like construction, perfect for
keeping an unyielding hold on anything it bites into. This style of tooth is
known as tricuspid. Despite the fearsome appearance of its teeth the shark poses
absolutely no threat to humans. The worst one could expect is a bite on the hand
from a scientist examining one.
The shark’s usual diet consists of other sharks, small squid, and various bony
fish. In essence, anything it can tear a chunk out of that lives on its depth
The Frilled Shark’s proper name is Chlamydoselachus anguineus. It is the only member of the Chlamydoselachidae family in the Hexanchiformes order making it exceedingly rare.
usual habitat is deep, cold ocean water in startlingly different places as the
map shows. The spots outlined in the brighter blue are the locations around the
world where the Frilled Shark has been most frequently sighted.
Most impressively, a female Frilled Shark was captured alive off the coast of
Japan in 2007. It was initially discovered by local fishermen who described it
to scientists as an ‘eel-like creature with razor-sharp teeth’. The Japanese
scientists, upon investigating the call, quickly captured the Frilled Shark and
brought it to an aquarium where they were able to record it swimming.
Unfortunately the shark died several hours later. Scientists have since
theorized that the reason for its being near the surface of the water, a rarity,
was due to some injury. The cause of its death is presumed to be the Frilled
Shark’s inability to adapt to the warm salt water of the aquarium tank. In
essence, the shock of the new environment as well as the aforementioned injury
resulted in its death.
Photograph taken from National Geographic
One particular mystery has been slowly clearing up thanks to tireless research. That is, namely, how the Frilled Shark reproduces. The answer is quite simply: A lot like how any other shark does. Via young developed inside the shark and birthed alive. The Frilled Shark procreates year round due, undoubtedly, to the whopping forty two month gestation period. That knocks the African Elephant, at 22 months, completely out of the water for longest vertebrate gestation period. Common theory holds that this is due to the fact that the Frilled Shark lives in the dark, deep, cold waters and so its metabolic rate among all other functions is significantly slower. The Frilled Sharks gives birth to litters of approximately six to twelve pups. Rather few for the average shark but given the Frilled Shark’s relatively small size, averaging between three to four feet, this can be expected. In fact, the female shark is often the larger, growing closer to that four foot mark, and it is assumed that the extra space it taken up by womb to allow the pups room to develop properly.
Despite the average being three to four feet there have been cases of the Frilled Shark growing up to six feet. For a deep-ocean dweller that’s a tremendously large size.
taken from National Geographic
Despite the many millions of years the Frilled Shark has existed it shows very little in the way of evolution. It has retained the same basic shape and function from its inception nearly eighty four million years ago. A telling sign of just how perfectly adapted to their environment sharks are and what a perfect species they have become through millions of years of highly specialized, nearly unnoticeable, evolution.