12 Facts About Great White Sharks

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In 1974, Peter Benchley released Jaws, a horror novel that sold 20 million copies, spawned an iconic film—and catapulted the great white shark (Carcharodon carcharias) to infamy. Although the book brought him fame and fortune, Benchley came to rethink its negative portrayal of great whites: The author-turned-conservationist said in 1995 that if he was writing his book then, “The shark … could not be the villain; it would have to be written as the victim.” The great white is now classified as a vulnerable species. Read on to find out why the truth about Carcharodon carcharias is often stranger—and always more compelling—than the fiction that obscures it.

1. EYE-ROLLING IS A DEFENSE MECHANISM.

Many sharks protect their eyeballs with a pair of clear lid structures called nictitating membranes, which act like protective, transparent eyelids. But not great whites—they don't have the membranes. Instead, their eyeballs roll backwards into the skull reflexively when a shark bites into a thrashing victim [PDF]. This exposes the sclerotic coat, a fibrous tissue that surrounds the eye.

2. SOME REPORTS ON THEIR SIZE ARE KIND OF FISHY.

The great white is a huge fish, no question—but some claims about its maximum size are probably exaggerated. In 1870, one zoologist measured the disembodied jaws of a large adult and estimated that the whole shark must have been 36.5 feet long. But a modern reevaluation—in which the jaws were compared to those from other dead sharks—showed that the creature’s actual length was probably about 16.5 feet, and the reports of the giant shark were likely a printer’s error.

And then there's the Cojímar specimen, a great white captured and killed near Cuba in the early 1940s. Those who saw it in person said the fish was 21 feet long and weighed 7100 pounds. Since then, the claim has been disputed by fish experts who, using an available photo, calculated that the animal’s real length was also in the ballpark of 16 feet. According to biologist Jose Castro’s book The Sharks of North America, the largest great white “believed to have been measured reliably” stretched 19.6 feet long. When it comes to weight, big males have been measured weighing up to 2819 pounds while the largest female weighed 4343 pounds.

3. GREAT WHITES ARE CLOSELY RELATED TO MAKOS.

According to a 2016 paper, there are 509 species of shark divided into nine orders and 34 families. Great whites belong to the lamnidae family, which contains only four other species: the porbeagle, the salmon shark, the longfin mako, and the shortfin mako. All five sharks have conical snouts, eyes that look solid black, and lengthy gill openings. They share a couple of other things as well—including a method for trapping body heat.

4. THEY CAN STAY WARM IN FRIGID WATER.

Most shark species have no direct control over their body temperatures; they're about as hot or cold as the water they’re swimming in. But there are a handful of species—the entire lamnidae family included—that are endothermic, meaning they can consistently maintain high body temperatures even in cold water.

The great white and its relatives have their powerful muscles to thank for this talent. The muscles naturally produce heat as they contract, warming up blood in that area, which is then redistributed to other parts of the body. This allows great whites to keep their core body temperature as high as 25 degrees (Fahrenheit) warmer than the ambient water, which means they can thrive in bitterly cold places. And when muscles are kept warm, they work more efficiently, so great whites can swim faster and farther than many other sharks. On the flip side, great whites need to consume a huge amount of calories in order to keep their body temperatures up.

5. NOT ALL GREAT WHITES GO AFTER THE SAME FOODS.

Great whites have varied diets and not all individuals share the same food preferences. But in general, younger sharks mostly eat fish and squids while older, larger sharks tend to go after big targets like marine mammals. Catching small fish and biting into fatty seals are, of course, two very different tasks. This explains why juvenile white sharks have narrower teeth than adults do—the better to pierce the skins of slippery fish. Living sharks of every species possess multiple tooth rows and are constantly replacing old chompers with brand new ones. As a great white matures, its incoming teeth become broader, serrated, and triangle-shaped, allowing great white adults to tear large chunks of meat off their victims.

6. GREAT WHITES CAN GET AIRBORNE.

Fatty, calorie-rich pinnipeds like seals and sea lions are common prey for large great whites, which typically attack from below in an explosive burst. The top speed of a great white is over 20 miles per hour, and during seal hunts, they can burst completely out of the water—a feat known as breaching—which leads to the successful capture of a pinniped 40 to 55 percent of the time, depending on lighting and other variables.

7. THEY DINE ON THE WORLD’S BIGGEST FISH.

In the 1960s, a 14.7-foot great white shark was captured near an Australian whaling station and, when it was dissected, two mysterious bones were found in its stomach. They were later identified as vertebrae belonging to an adult whale shark that was estimated to be 28 feet long. These filter feeders can grow to be 40 feet long and weigh at least 7 tons; experts now think that great whites are scavenging on floating whale shark carcasses rather than hunting the fish.

8. ATTEMPTS TO PUT THEM IN CAPTIVITY HAVEN’T GONE WELL.

Certain sharks thrive in aquariums; great whites don’t. Every single great white that’s been placed in captivity has either died or been released after a brief stay. The Okinawa Aquarium, Sea World San Diego, and the now-defunct Marineland of the Pacific are among the facilities which experimented with captive white sharks at some point or other. At the Monterey Bay Aquarium, one specimen spent a record-breaking six months living in a million-gallon tank. Once she began stalking other display fish, however, she was set free. Several different factors make great whites ill-suited for captivity. To breathe, the animals must be in constant motion to push water over their gills, and aquariums don’t always offer enough space for this. Other issues include the species’ famously large appetite and its tendency to run into glass walls.

9. DESPITE MYTHS TO THE CONTRARY, GREAT WHITES CAN GET CANCER.

There’s a myth that great whites and other sharks are immune to cancer, which has had some unfortunate real-world consequences. Assertions that shark cartilage is an edible cancer cure has led to mass harvesting of the vulnerable fish.

For the record, clinical tests have shown that ingesting shark cartilage in no way treats any form of cancer. Cancer has been documented in more than 20 shark species, including the great white: The first reported instance of a tumor-plagued great white was announced in 2015.

10. THEY TRAVEL VAST DISTANCES.

The great white inhabits many of the world's oceans, but they're most often found in waters with surface temperatures from 59°F to 72°F. The species also migrates seasonally. Some travel from South Africa to Australia and back every year. Other great whites cross the Atlantic, making long treks between Cape Cod, Massachusetts and the Azores, 2300 miles away. And each winter, scores of them leave Californian waters for a point researchers have nicknamed “the white shark café.” Located halfway between Hawaii and Mexico, this region doesn’t appear to offer much in the way of food, but the sharks remain there from April to July. Data from tagged great whites tells us that the males go on rapid, deep dives multiple times per day while hanging out in this area. Nobody knows why the white shark café is such a hot destination—but it might be a place where the fish gather to breed.

11. ORCAS PREY ON THEM.

When great whites get knocked upside-down, they freeze up and exhibit “tonic immobility,” a state of semi-consciousness. There’s at least one animal that can exploit the vulnerability. On October 4, 1997, an orca was seen barreling towards a great white shark (which measured 9 to 13 feet long) near one of California’s Farallon Islands. A human onlooker filmed the orca dragging the stunned fish around on its backside. Eventually, it let go [PDF], and then ate the dead shark's liver.

Between May and the end of June 2017, the bodies of four white sharks—all missing their livers—washed onto South African beaches. All four deaths have been attributed to orcas. A great white’s liver is high in fat and loaded with nutrients, which may account for the orcas’ interest in singling it out for consumption. One of the sharks had its testicles and stomach missing as well.

12. DO THEY REALLY MISTAKE PEOPLE FOR SEALS? PERHAPS NOT.

Though shark-on-human attacks are rare, most of the time, when you do hear about an attack, a great white is behind it. Since 1580, Carcharodon carcharias has been positively identified in at least 314 unprovoked attacks on humans (80 of them fatal). No other shark species is credited with even half as many.

According to one common explanation, great whites attack humans because they mistake them for pinnipeds. The argument goes that, when viewed from below, a person on a surf board projects a seal-like silhouette.

While this is a popular idea, it leaves some critical things unexplained. First of all, great whites have proportionally large eyes by shark standards—and acute vision to boot. Also, the big fish strike seals with tremendous force at great speed; by comparison, the sharks usually move at a slow, deliberate pace when approaching people. And in the vast majority of attack incidents, a great white will deliver a single bite and then leave without consuming the victim. In fact, nearly three out of every four humans who get bitten by white sharks survive the encounter.

Biologists have proposed that when the animals bite people, they do so out of curiosity (at least, in most cases). “Great whites are curious and investigative animals. That’s what most people don’t understand,” marine biologist R. Aidan Martin told National Geographic. “When great whites bite something unfamiliar to them, whether a person or a crab pot, they’re looking for tactile evidence about what it is.”

The sharks often go out of their way to nibble on inanimate objects—such as underwater cameras—before losing interest and moving on. So maybe, when they decide to bite people, they're not looking for a snack.

10 Colorful Facts About Cassowaries

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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.

Notre-Dame's Rooftop Bees Survived the Historic Fire

Dan Kitwood/Getty Images
Dan Kitwood/Getty Images

Following the fire that tore through Notre-Dame in Paris on April 15, fire officials shared that the church's bell towers, stone facade, and many of its precious artifacts had escaped destruction. But the building's centuries-old features weren't the only things threatened by the blaze: The three beehives on the roof of the cathedral were also at risk. Now, CNN reports that the bees of Notre-Dame and their homes have survived the historic fire.

Notre-Dame's beehives are a relatively recent addition to the site: They were placed on the first-floor rooftop over the sacristy and beneath one of the rose windows in 2013. Nicolas Geant, the church's beekeeper, has been in charge of caring for the roughly 180,000 Buckfast bees that make honey used to feed the hungry.

Most people weren't thinking of bees as they watched Notre-Dame burn, but when the fire was put out, Geant immediately searched drone photographs for the hives. While the cathedral's wooden roof and spire were gone, the beehives remained, though there was no way of knowing if the bees had survived without having someone check in person. Geant has since talked to Notre-Dame's spokesperson and learned that bees are flying in and out of the hives, which means that at least some of them are alive.

Because the beehives were kept in a section 100 feet below the main roof where the fire was blazing, they didn't meet the same fate as the church's other wooden structures. The hives were likely polluted with smoke, but this wouldn't have hurt the insects: Bees don't have lungs, so smoke calms them rather than suffocates them.

Notre-Dame's bees may have survived to buzz another day, but some parts of the building weren't so lucky. France has vowed to rebuild it, with over $1 billion donated toward the cause so far.

[h/t CNN]

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