If shoppers have one complaint about Costco—the vast discount warehouse chain with a notoriously permissive return policy and speedy checkout lanes—it’s that the employees posted at the exits to take a marker to customers' receipts seem vaguely insulting. Is the premise that everyone is a shoplifter until proven otherwise?
Not exactly. A recent rundown of Costco's policy from The Takeout (via Cheat Sheet) points out that the true motivation of these exit-door sentries isn’t to identify potential thieves. It’s to make sure that Costco isn’t picking the pockets of its customers.
According to employees who have made not-for-attribution comments, Costco is actually examining receipts to make sure a shopper hasn’t been overcharged for their purchases. Someone with three giant bundles of toilet paper in their cart, for example, might have been charged for four. By giving the receipt a cursory glance, the employee can make sure a cashier didn’t inadvertently ring up phantom crates of canned tuna.
Of course, if someone did try to wheel out several big-screen televisions without a receipt, the exit door employee would likely make an issue of it. But they’re not in loss prevention, and the measure isn’t intended to deter thieves. If you do have something in your cart you didn’t pay for, their immediate assumption is that the mistake is almost certainly the result of a cashier not scanning the item.
In fact, hardly any criminals are caught at the door—which isn't to say the store isn't immune to theft. Earlier this year, thieves at a Seattle Costco were busted with armloads of laptops after they barged out of the back entrance. In June, a Costco in Alpharetta, Georgia, was victimized by burglars who smashed the jewelry case at night and made off with $10,000 worth of valuables.
Game of Thrones is a show that requires a serious suspension of disbelief. It exists in a universe where the dead can rise from their graves, humans can see through the eyes of animals, anyone can travel between Dragonstone and Eastwatch at or near the speed of light, and Jon Snow can hold an unbroken frown for seven straight seasons.
Still, as we anticipate the premiere of Game of Thrones's eighth and final season on April 14—and as we remember cowering each time Drogon hovered in midair to pour a throatful of flame over one of Daenerys Targaryen’s enemies in last season's big-budget battles—we started to wonder: Could a beast that big really maneuver through the air like that? Fortunately, two scientists who have dedicated their lives to studying flying creatures agreed to clear that up for us.
Kevin McGowan, a Cornell ornithologist who specializes in crows, says there’s one major problem with dragon flight: physics. “They’re just so damn big,” he says. “Way too big to ever get off the ground.”
For comparison, there's the albatross, which weighs around 25 pounds and needs a 10-foot wingspan in order to heave itself into the air. And birds don’t scale up easily. McGowan says that as a bird gets heavier, its wingspan has to grow exponentially to keep up: “If you need a 10 foot wingspan for a 25-pound bird, what would you need for a 2000-pound dragon?” (Last season, one eagle-eyed engineer estimated that Drogon weighed around three tons and flew with a wingspan under 60 feet—and the dragons are even bigger now.)
In the real world, bird species generally stay small to avoid having to grow their wings exponentially. Those that do grow large wings, like the albatross, can travel long distances—but pay the price in maneuverability. Birds with smaller wings can maneuver in tighter spaces, but have to expend much more energy to stay aloft. “Birds make a lot of compromises to fly,” McGowan says, “and dragons just aren’t doing that.”
Still, there is some hope for letting our dragon-sized fantasies take flight. Michael Habib, a paleontologist and assistant professor of clinical integrative anatomical sciences at the University of Southern California's Keck School of Medicine, studies the flight mechanics of extinct animals, including giant pterosaurs once thought to be too big to get off the ground. He also works with film studios like Disney, Marvel, and Lucasfilm to design believable flying monsters like griffins, hippogriffs, and pegasi. There are three tricks, he says, for plausibly scaling up fantasy flying creatures.
First, you want to give them the right wing type. Like modern day bats, pterosaurs—which lived from 228 to 66 million years ago—had membrane wings, made of skin stretched over a series of elongated fingers. These are good for slow, maneuverable flight, and they don’t have to be as large compared to the body as a bird’s feather wings. Habib tells Mental Floss that a dragon with a good pair of wings would be able to sustain flight easily once it was in the air—but it could only get there “if it came with a catapult for takeoff.”
Second, a dragon needs to have the right skeletal structure. Their bones should be strong enough to withstand the massive mechanical forces involved in flight without getting too heavy. Hollow bones are best; they're actually stronger than a very dense bone with a similar mass. Habib explains that’s because the bone’s ability to withstand the strain of flight depends on its diameter—the wider it is, the more force it can take. A hollow, air-filled bone can be much wider than a dense bone full of marrow, and it will still weigh less than the dense bone.
Third, and most importantly, a dragon needs to have as much power available for takeoff as possible. Habib says that almost every animal that takes flight, from birds to flying squirrels to winged snakes, gets into the air by jumping, not flapping its wings.
“What birds get stuck on is they only have two hind limbs available for jumping power,” Habib says. “Bats do better—and pterosaurs did, too—because they walk on their wings and they can jump off of all four limbs.”
That makes a big difference, especially because most of a bird’s strength is in its wings. While birds take off with less than half their bodies’ muscle power, bats and pterosaurs launch themselves with everything they’ve got. That’s what allowed the largest pterosaurs to grow into 550-pound behemoths, while the heaviest-ever flying bird—the extinct Argentavis magnificens—maxed out around 150 pounds.
The dragons in Game of Thrones do have membrane wings, and they could conceivably have hollow bones. Back in season three, WIREDreported that the show’s animators based the dragons on a cross between an eagle and a bat. (Their strenuous, flappy hovering certainly takes after fruit bats.) Although the dragons walk around on their wings like bats, they don’t seem to jump off of them during takeoff. Throughout the series, we see them dive from cliffs and glide into flight, leap off their hind legs after a running start, and sometimes just flap their wings and leave the ground.
Habib says even if a dragon followed all of his specifications, it could only grow up to about 1000 pounds without grounding itself—not several tons, like Daenerys’s children.
“They’re probably beyond the flight limit for any anatomy,” Habib concedes, “unless they’re secretly made out of carbon fiber and titanium.”
“Maybe they’re full of hot air,” suggests McGowan, “or maybe it’s just magic.”
And what would happen if a dragon got a hole in one of its membrane wings, like Viserion displays after rising from the dead in the finale of season seven? Could it still fly? "The short answer is, probably a bit, but not as well as normal," Habib says.
Bats can fly with similarly damaged wings thanks to the way wings move through air. We tend to think of them as paddles pushing the air, but wings actually pull air. Like any other fluid, air has a certain amount of intrinsic stickiness to it, so air sticks to other air. "As the wing is pulling on the air, it's flowing over and around the wing, and it will skip over the air within the wing's small gaps and imperfections just as water will jump over the holes in a storm grate," Habib says. "Obviously, the more holes you put in the wing, the more inefficient it becomes, but it will still work up to a point. If there are too many holes, it will fail."
To McGowan, though, how the dragons fly doesn't really matter: “I think all day. When I go home, I don’t want to think anymore. I can just say it’s magic. I don’t care.”
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By now, you may have heard the peculiar explanation of how witches and wizards in J.K. Rowling’s universe relieved themselves before modern-day plumbing. As Entertainment Weekly reports, a section of the Pottermore website pertaining to the Chamber of Secrets entrance (which, if you recall, was in Moaning Myrtle’s bathroom) states that Hogwarts adopted plumbing in the 18th century. Before that, spells were cast to eliminate excrement—or perhaps blast it into another dimension.
“Hogwarts’ plumbing became more elaborate in the eighteenth century (this was a rare instance of wizards copying Muggles, because hitherto they simply relieved themselves wherever they stood, and vanished the evidence),” the site states in an essay by Rowling. This was initially revealed in 2015, but Pottermore's recent tweet on the subject has been causing a stink.
Hogwarts didn't always have bathrooms. Before adopting Muggle plumbing methods in the eighteenth century, witches and wizards simply relieved themselves wherever they stood, and vanished the evidence. #NationalTriviaDay
A lot of people aren’t satisfied with this unsavory explanation—"witches and wizards, some highly sophisticated beings who created complex magical governments and tamed the fiercest beasts, at one point just pooped themselves,” Entertainment laments—but it’s worth noting that the claim does pass a historical fact check of sorts.
According to Rowling, Hogwarts was founded in the year 990 C.E.—more than 600 years before Sir John Harington, the godson of Queen Elizabeth I and a distant relative of Game of Thrones star Kit Harington, invented the first flush toilet. Even though this technology existed in the 16th century, Harington only made two toilets: One for himself and one for his royal godmother. The first patented flush toilet didn’t arrive until 1775, thanks to a different design by watchmaker (and toilet inventor) Alexander Cummings. So the timing checks out.
Of course, people didn’t just pee themselves or pop a squat on the ground prior to working toilets, which is why so many people are baffled by Rowling’s explanation. Chamber pots and outhouses were used throughout much of human history, and members of the British ruling class had more luxurious arrangements. In the 16th century, King Henry VIII did his business atop a padded chair—covered in sheepskin, black velvet, and ribbons—with a chamber pot beneath it. However, male courtiers did sometimes do their business wherever they felt like it (palace stairwells were one popular location in France).
As for Hogwarts’ plumbing situation, it may sound like a gross and unnecessary detail, but it’s actually relevant to the story. According to a Pottermore essay penned by Rowling, the entrance to the Chamber of Secrets was nearly revealed when the school decided to build a bathroom on the site. However, a student and direct descendent of Slytherin named Corvinus Gaunt played a part in concealing its entrance—“even after newfangled plumbing had been placed on top of it.”