11 Fascinating Facts About the Frilled Shark

Sometimes called a “living fossil” because it has changed so little since prehistoric times, the eel-like frilled shark—which is rarely seen by humans—has been in the news this week after a snake-like one was found off the coast of Portugal. Here’s a quick primer.

1. IT’S NAMED FOR ITS GILLS.

Its scientific name is Chlamydoselachus anguineus, but this creature’s common name comes from its gills: Unlike all other sharks, which have separate gills, C. anguineus’ first pair of gills go all the way across its throat; each pair is lined at the edges with red “fringe.”

2. IT WAS DISCOVERED IN THE 19TH CENTURY.

The sharks were first scientifically described by German ichthyologist Ludwig H.P. Döderlein, who taught at Tokyo University from 1879 to 1881 and brought two specimens captured in Tokyo Bay when he returned to Vienna. His paper describing the sharks was lost, however, so the first description comes from Samuel Garman in the 1884 edition of the Bulletin of Essex Institute. In the remarks after the description, Garman noted that

Such an animal as that described is very likely to unsettle disbelief in what is popularly called the “sea serpent.” Though it could hardly on examination be taken for anything but a shark, its appearance in the forward portion of the body, particularly in the head, brings vividly to mind the triangular heads, deep-cleft mouths, and fierce looks of many of our most dreaded snakes. In view of the possible discoveries of the future, the fact of the existence of such creatures, so recently undiscovered, certainly calls for a suspension of judgment in regard to the non-existence of that oft-appearing but elusive creature, the serpent-like monster of the oceans.

The frilled shark’s species name, anguineus, is Latin for “consisting of snakes” or “snaky.”

Biologist David A. Ebert, director of the Pacific Shark Research Center, described a second frilled shark species—Chlamydoselachus africana, which lives off the coast of Africa and is about half as long as its predecessor—in 2009.

3. IT’S GOT INSANE TEETH.

The frilled shark’s mouth is just as terrifying as the maw of a great white: It’s lined with 25 rows of backward-facing, trident-shaped teeth—300 in all. “The teeth are constructed for grasping and from their peculiar shape and sharpness it would seem as if nothing that once came within their reach could escape them,” Garman wrote. “Even in the dead specimen the formidable three-pronged teeth make the mouth a troublesome one to explore.” 

Ebert can testify to that fact. “I can tell you from snagging my fingers on the teeth, you can only back out one way and that’s in toward the mouth and then out,” he told WIRED. “It didn’t feel good, I can tell you that.” The shark uses the bright white teeth, which sharply contrast against its brown body, to lure in prey: “By the time [the prey] realize, Oh, that’s the teeth of a shark, they’re too close and the shark is able to ambush them at that point,” Ebert said. “It’s almost like when you drive out of a parking lot exit and they have the spikes sticking out that say, ‘Do not back up.’ That’s kind of what happens when these things catch prey items.”

And as if its teeth weren’t freaky enough, the frilled shark has spines, called dermal denticles, lining its mouth. So if you happen to see one of these anywhere, it’s better to look and not touch.

4. IT “HOVERS” IN THE WATER...

Scientists once believed that the frilled shark wriggled through the water like an eel. But according to the ReefQuest Centre for Shark Research, “its body cavity is elongate and packed with a huge liver perfused with low-density oils and hydrocarbons, making the shark almost neutrally buoyant at depth.”

5. … AND IT MAY STRIKE AT ITS PREY LIKE A SNAKE.

No one has ever observed the frilled shark hunting, but scientists believe that it uses its posterior fins as propulsive surfaces to launch itself at its prey. Its long jaws, which terminate at the back of its head, may allow the animal to gape extra wide and take in prey half as long as its body. Analysis of the stomach contents of captured specimens has revealed that the frilled shark’s diet is 61 percent cephalopod, 11 percent teleost fishes, and, occasionally, other sharks.

6. IT’S FOUND ALL OVER THE WORLD—BUT YOU PROBABLY WON’T SEE IT.

The Food and Agriculture Organization of the United Nations notes that the frilled shark is “wide-ranging but spottily distributed”; you can see where the shark is found on the map above. It typically resides in depths between 390 and 4200 feet, so people rarely see these sharks unless they venture to the surface, which isn’t unheard of (as you’ll see below).

7. FEMALES ARE BIGGER THAN MALES.

On average, males range from 3.2 to 3.6 feet and females from 4.4 to 4.9 feet; the maximum these sharks can reach is 6.4 feet.

8. THEIR GESTATION PERIOD MAY BE 3.5 YEARS LONG.

A study of frilled sharks in Japan revealed that the animals breed year-round; litters typically consist of six pups, which emerge from eggs while still in the mother’s uterus and are then born live. Scientists think the shark may have the longest gestation period ever: Frilled sharks could gestate for as long as 42 months, nearly twice as long as African elephants carry their young. Scientists theorize that the extreme length has something to do with the shark’s cold deep sea habitat.

9. IT WASN’T SEEN IN ITS NATURAL HABITAT UNTIL 2004.

NOAA scientists exploring the “Latitude 31-30 Transect” in the Atlantic Ocean captured a video of a frilled shark “swimming over sea bottom that was covered with tiny sand dunes” during a submersible dive. “This species has been, on rare occasion, caught or taken in bottom trawls,” the site notes. “To the knowledge of everyone on board, however, this was the first time anyone had ever seen the rare species in its natural habitat.”

10. ONE WAS CAPTURED IN JAPAN IN 2007.

In January 2007, a Japanese fisherman spotted a strange, eel-like creature with a mouth full of sharp teeth near the surface; he alerted the staff of the Awashima Marine Park in Shizuoka, who captured the animal and transferred it to a seawater pool, where they filmed it. “We think it may have come close to the surface because it was sick, or else it was weakened because it was in shallow waters,” a park official said. “We believe moving pictures of a live specimen are extremely rare. They live between 600 and 1000 meters under the water, which is deeper than humans can go.” The shark, a female, died a few hours after its capture.

11. IT CALLS ANOTHER FREAKY SHARK ITS COUSIN.

The frilled shark might have rows upon rows of gnarly teeth, but its cousin, the goblin shark, can thrust its jaw out of its face. Which is more terrifying?

14 Adorable, Vintage Photos of Rabbits

Chaloner Woods, Getty Images
Chaloner Woods, Getty Images

In honor of International Rabbit Day (held annually on the fourth Saturday of September), we've pulled photographic proof that the furry little mammals have always been appreciated by children and the adults who use a number of rabbit-related phrases and idioms more often than they probably realize.

1. DOWN THE RABBIT HOLE

Nursery school children playing with their pet rabbit Bubbles; 1939.
David Parker, Fox Photos/Hulton Archive/Getty Images

Nursery school children playing with their pet rabbit Bubbles, 1939.

2. DUST BUNNY

 A woman spinning Angora rabbit wool in her garden, 1930.
Fox Photos, Getty Images

A woman spinning Angora rabbit wool in her garden, 1930.

3. MAD AS A MARCH HARE

A young boy holds a pet rabbit, 1955.
Charles Ley, BIPs/Getty Images

A young boy holds a pet rabbit, 1955.

4. BUY THE RABBIT

A golfer makes a practice drive while his pet rabbit minds the balls; 1938.
Reg Speller, Fox Photos/Hulton Archive/Getty Images

A golfer makes a practice drive while his pet rabbit minds the balls, 1938.

5. HONEY BUNNY

School children petting rabbits; 1949.
Chaloner Woods, Getty Images

Schoolchildren petting rabbits, 1949.

6. HAREBRAINED IDEA

A woman took her Himalayan rabbit, Albrecht Durer, on a walk in Hyde Park, 1939.
Fox Photos, Getty Images

A woman took her Himalayan rabbit, Albrecht Durer, on a walk in Hyde Park, 1939.

7. CUDDLE BUNNY

A little girl petting a large rabbit, 1949.
Chaloner Woods, Getty Images

A little girl petting a large rabbit, 1949.

8. LUCKY RABBIT'S FOOT

Schoolgirls care for pet rabbits, 1932.
Fox Photos, Getty Images

Schoolgirls care for pet rabbits, 1932.

9. PULL A RABBIT OUT OF A HAT

A young magician and his rabbit, 1971.
George W. Hales, Fox Photos/Getty Images

A young magician and his rabbit, 1971.

10. SNOW BUNNY

A woman shows off her two pet angora rabbits, circa 1955.
George Pickow, Three Lions/Getty Images

A woman shows off her two pet angora rabbits, circa 1955. Angoras can be sheared to provide enough wool for two sweaters each year.

11. THE EASTER BUNNY

A little girl holds an Easter bunny on a leash, circa 1955.
George Pickow, Three Lions/Getty Images

A little girl holds an Easter bunny on a leash, circa 1955.

12. A RABBIT TRAIL

Three children hold a rabbit, 1935.
H. Allen, Topical Press Agency/Getty Images)

Three children hold a rabbit, 1935.

13. RABBIT FOOD

A boy feeds his pet rabbit a lettuce leaf, circa 1955.
George Pickow, Three Lions/Getty Images

A boy feeds his pet rabbit a lettuce leaf, circa 1955.

14. RABBITING ON

Actresses Fiona Fullerton and Clare Clifford posting some of the many letters sent to the House of Lords and parliamentary candidates to request support for World Day for Laboratory Animals which was instituted that year, 1979.
Central Press, Getty Images

Actresses Fiona Fullerton and Clare Clifford posting some of the many letters sent to the House of Lords and parliamentary candidates to request support for World Day for Laboratory Animals which was instituted that year, 1979.

How a Wildlife Center Untangled Five Squirrels' Tails

Wisconsin Humane Society
Wisconsin Humane Society

Five juvenile gray squirrels in Wisconsin found themselves in a hairy situation recently. As The Guardian reports, bits of plastic and grass from their mother's nest got caught in their tails. Then the five tails became entangled, forming one solid knot.

This could have been a fatal situation had it not been for a "caring finder" who happened upon the squirrels and brought them to the Wildlife Rehabilitation Centre at the Wisconsin Humane Society in Milwaukee.

"You can imagine how wiggly and unruly (and nippy!) this frightened, distressed ball of squirrelly energy was, so our first step was to anesthetize all five of them at the same time," the rehabilitation center wrote in a Facebook post on September 14. "With that accomplished, we began working on unraveling the 'Gordian Knot' (Google it) of tightly tangled tails and nest material." (For the record, a Gordian knot refers to a difficult problem and stems from a legend involving Alexander the Great.)

Next, they used scissors to carefully cut away the plastic and grass while taking care not to snip their tails, which had already sustained tissue damage due to the blood supply being cut off. After about 20 minutes, they were finally freed. Now, the squirrels have fully recovered and are "very active and vigorous." Staff at the center are still watching for signs of tail necrosis—the death of cells and tissue—but otherwise, the fur babies are expected to make a full recovery.

Tangled tails are not uncommon in the animal kingdom. A group of rats with entangled tails is called a "rat king," and the phenomenon has been reported since at least the mid-16th century. There's no equivalent term for when this happens to squirrels, although it does occur from time to time.

[h/t The Guardian]

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