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?

20 Black-and-White Facts About Penguins

iStock/fieldwork
iStock/fieldwork

Who is a penguin's favorite family member? Aunt Arctica! 

We kid! But seven of the 17 species of penguins can be found on the southernmost continent. Here are 20 more fun facts about these adorable tuxedoed birds. 

1. All 17 species of penguins are found exclusively in the Southern Hemisphere.

A group of penguins on an iceberg.
iStock/axily

2. Emperor Penguins are the tallest species, standing nearly 4 feet tall. The smallest is the Little Blue Penguin, which is only about 16 inches.

Three emperor penguins
iStock/Fabiano_Teixeira

3. The fastest species is the Gentoo Penguin, which can reach swimming speeds up to 22 mph.

A gentoo penguin swimming underwater
iStock/chameleonseye

4. A penguin's striking coloring is a matter of camouflage; from above, its black back blends into the murky depths of the ocean. From below, its white belly is hidden against the bright surface.

Penguins swimming in the ocean
iStock/USO

5. Fossils place the earliest penguin relative at some 60 million years ago, meaning an ancestor of the birds we see today survived the mass extinction of the dinosaurs.

Emperor penguins with chicks
iStock/vladsilver

6. Penguins ingest a lot of seawater while hunting for fish, but a special gland behind their eyes—the supraorbital gland—filters out the saltwater from their blood stream. Penguins excrete it through their beaks, or by sneezing.

Penguin swimming in the ocean
iStock/Musat

7. Unlike most birds—which lose and replace a few feathers at a time—penguins molt all at once, spending two or three weeks land-bound as they undergo what is called the catastrophic molt.

Gentoo penguin chick molting
iStock/ChristianWilkinson

8. All but two species of penguins breed in large colonies of up to one thousand birds.

A colony of king penguins
iStock/DurkTalsma

9. It varies by species, but many penguins will mate with the same member of the opposite sex season after season.

Two chinstrap penguins
iStock/Legacy-Images

10. Similarly, most species are also loyal to their exact nesting site, often returning to the same rookery in which they were born.

Magellanic penguin nesting in the ground
iStock/JeremyRichards

11. Some species create nests for their eggs out of pebbles and loose feathers. Emperor Penguins are an exception: They incubate a single egg each breeding season on the top of their feet. Under a loose fold of skin is a featherless area with a concentration of blood vessels that keeps the egg warm.

Penguin eggs
iStock/Buenaventuramariano

12. In some species, it is the male penguin which incubates the eggs while females leave to hunt for weeks at a time. Because of this, pudgy males—with enough fat storage to survive weeks without eating—are most desirable.

A group of emperor penguins and chick
iStock/vladsilver

13. Penguin parents—both male and female—care for their young for several months until the chicks are strong enough to hunt for food on their own.

Penguin chick and parent on a nest
iStock/golnyk

14. If a female Emperor Penguin's baby dies, she will often "kidnap" an unrelated chick.

Three emperor penguin chicks
iStock/AntAntarctic

15. Despite their lack of visible ears, penguins have excellent hearing and rely on distinct calls to identify their mates when returning to the crowded breeding grounds.

Gentoo penguins
iStock/Goddard_Photography

16. The first published account of penguins comes from Antonio Pigafetta, who was aboard Ferdinand Magellan's first circumnavigation of the globe in 1520. They spotted the animals near what was probably Punta Tombo in Argentina. (He called them "strange geese.")

A group of magellanic penguins on the seacoast
iStock/encrier

17. An earlier, anonymous diary entry from Vasco da Gama's 1497 voyage around the Cape of Good Hope makes mention of flightless birds as large as ducks.

A cape penguin in South Africa
iStock/ziggy_mars

18. Because they aren't used to danger from animals on solid ground, wild penguins exhibit no particular fear of human tourists.

Man videotaping a penguin in Antarctica
iStock/Bkamprath

19. Unlike most sea mammals—which rely on blubber to stay warm—penguins survive because their feathers trap a layer of warm air next to the skin that serves as insulation, especially when they start generating muscular heat by swimming around.

Penguin swimming in the ocean
iStock/Musat

20. In the 16th century, the word penguin actually referred to great auks (scientific name: Pinguinus impennis), a now-extinct species that inhabited the seas around eastern Canada. When explorers traveled to the Southern Hemisphere, they saw black and white birds that resembled auks, and called them penguins.

This story was first published in 2017.

10 Colorful Facts About Cassowaries

iStock/BirdImages
iStock/BirdImages

All birds are living dinosaurs, but the dagger-clawed cassowary especially looks the part. Even wildlife biologists call cassowaries the world's most dangerous bird—and yes, it has been known to kill people. Here’s everything you need to know about the majestic and terrifying beast.

1. The southern cassowary is Earth's second-heaviest bird.

Scientists recognize three living species of cassowary—all of which live in New Guinea, northeastern Australia, and nearby islands. The dwarf cassowary is the smallest, with an average height of around 3 feet. The northern cassowary, an orange-throated behemoth, can stand nearly 5 feet tall. The southern cassowary is bigger than both at 5 foot 6 inches tall. The only two birds that grow taller are ostriches and emus. Adult southern cassowary females can weigh up to 157 pounds, and males 121 pounds, making them the second-heaviest birds on the planet behind ostriches.

2. Cassowaries have dangerous feet.

In the southern cassowary's Australian range, you might come across warning signs that read “Be Cass-o-wary.” Heed this advice. Normally, cassowaries are shy and reclusive, but they can become aggressive when threatened and strike back with powerful head-butts and pecks. Their most dangerous weapon is the razor-sharp claw on the middle toe of each foot, which, in southern cassowaries, grows to be 5 inches long. The birds deliver a series of downward kicks that have been known to break bones and cause fatal lacerations. 

3. Rearing cassowary chicks is the father's job.

Female cassowaries breed with several partners. After laying her eggs, she abandons them, at which point the males take over and incubates the eggs for at least 50 days. The fathers never leave the nest, not even to eat or drink. Once the eggs hatch, males spend the next nine months raising and defending the chicks. Males also teach the chicks how to forage so they can fend for themselves.

4. Cassowaries are surprisingly good jumpers.

What’s scarier than a 150-pound modern dinosaur with killer claws? One that can leap 7 feet off the ground. To get the most out of those toe daggers, cassowaries will sometimes jump feet-first at an attacker, with the claws slashing downward in midair. They’re also great swimmers and sprinters with a top running speed of 30 miles per hour.

5. Cassowaries have a spike hidden on each wing.

Cassowaries are closely related to emus and more distantly related to ostriches, rheas, and kiwis. All of these birds, known as ratites, are flightless. Cassowaries have small vestigial wings tipped with a small claw that probably serves no purpose.

6. Cassowaries are frugivores that also eat their own poop.

Wild cassowaries dine mainly on fruits and berries that fall to the ground in the rainforests they call home. A typical southern cassowary can eat up to 11 pounds of fruit a day, along with plenty of fungi and the occasional dead animal for some extra protein.

Cassowaries also hunt rodents, snails, and lizards. Poop is yet another item on the menu. Cassowary poop usually contains half-digested fruit, which still has plenty of nutritional value, so the birds devour each other’s droppings as well as their own. 

7. The function of their odd crests, or casques, is a mystery. 

Cassowaries sport royal-blue necks and shaggy black feathers, but their most distinctive feature is the helmet-like casque that sits above the eyes. The bony protrusion is covered with a sheath of keratin (the material that makes up your fingernails), and it begins to develop when the bird is around 2 years old. Scientists have long speculated, sometimes wildly, about its purpose. One theory is that casques help cassowaries push aside forest underbrush. The casques might also be used to attract the opposite sex.

A more interesting hypothesis involves how these birds communicate. Cassowaries emit very deep bellows—the lowest bird calls known to humans. Perhaps their casques amplify and broadcast these sounds by acting as a resonance chamber. Certain crested dinosaurs (like Parasaurolophus of Jurassic Park fame) may have produced calls the same way.

8. Cassowaries can live for decades (at least in zoos).

Naturalists don’t know how long a wild cassowary can expect to live. A few southern cassowaries have reached their 40th birthdays in captivity. In zoos, northern cassowaries can top that figure—one reached the age of 48 and another may have been as old as 61. The average lifespan for captive dwarf cassowaries is about 26 years.

9. Cassowaries have strange genitalia.

Both sexes have a pseudo-penis that isn’t connected to any of their internal reproductive organs. When cassowaries mate, the male ejaculates through his cloaca, an orifice at the base of the pseudo-penis. When they aren’t mating, males' pseudo-penis is turned inside out and retracted.

Such peculiar anatomy has given the cassowary a unique place in New Guinean culture and folklore. For example, the native Mianmin people tell stories about a human woman with a penis who somehow transformed into a cassowary. Another indigenous group, the Umeda, put on a regular ceremony called “ida.” A big event that lasts for two days and nights, the ritual involves a fertility dance which calls for two male dancers who represent a pair of cassowaries. Each player is given a heavy mask and is coated with charcoal from head to toe.

10. At least two unfortunate humans have been killed by cassowaries. 

To date, there have been only two verified reports of a cassowary taking human life. In April 1926, a cassowary fatally charged 16-year-old farmer Phillip McLean in north Queensland, Australia. More recently, a 75-year-old Florida man was killed by a cassowary he had kept as a pet at his exotic bird farm.

In 1999, Queensland Parks and Wildlife ranger Christopher P. Kofron analyzed 150 documented cassowary-on-human attacks. Twenty-two percent of attacks resulted from the bird defending itself, its eggs, or its chicks, 5 percent were triggered by somebody getting too close to the cassowary’s food, and 73 percent involved a cassowary that associated people with free meals. Many cassowaries in Australia had lost their natural shyness around humans thanks to people feeding them bananas and watermelon. Today, feeding a wild one is against the law, but the practice continues.

SECTIONS

arrow
LIVE SMARTER