What Is the Fastest Animal in the World?


People seem to have an innate fascination with speed. We like to watch high-performance cars circle tracks—or tempt speed limits on highways ourselves—and celebrate Olympic athletes like Usain Bolt, who probably is the fastest man on two feet at the moment.

That curiosity often extends beyond machines and elite athletic competition. What has nature done to gift certain animals with enough momentum to overcome prey? And is there really such a thing as the fastest animal in the world?

If all we really want to determine is which animal can cover the distance from point A to point B in the shortest amount of time, then that lingering fact you may have heard about cheetahs is true. The sinewy cat found mainly in Africa can hit speeds of 64 mph, roughly the speed limit of many major U.S. highways. (Other studies have pegged it at 58 mph.)

That’s under ideal conditions. Normally, cheetahs sprint because they’re after dinner, and if that dinner tries to evade capture, the cheetah will need to stop and resume speed often to keep up. Because of the unpredictable nature of their prey, a cheetah often keeps its speed closer to 33 mph.

When we associate the fastest animal in the world with linear forward movement on land, the cheetah is probably going to come out on top. But not all animals use limbs to propel themselves vertically. The falcon, for example, takes advantage of gravity to descend on prey from above. Like free-falling parachutists, falcons have been known to reach high speeds on descent. The higher the starting point, the more speed they can achieve: One peregrine falcon that began at 15,000 feet (thanks to some human help) reached 183 mph.

The cheetah is also outperformed in water by the sailfish, which can reach speeds of 68 mph when they're breaching waves. For context, a sailfish could swim 200 meters in just 10 seconds; Michael Phelps would need well over a minute to cover the same distance. Killer whales can swim 34 mph—incredibly speedy considering their heft.

Asking which is the fastest animal in the world is a tricky question. Humans tend to think of "fast" in relation to the linear movement we see in racing, but fast can mean a variety of things in the wild. While you may never see most of these animals shift into gear in person, at least one domesticated creature can hit the gas: The greyhound tops out at 43 mph.

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How Did 6 Feet Become the Standard Grave Depth?


It all started with the plague: The origins of “six feet under” come from a 1665 outbreak in England. As the disease swept the country, the mayor of London literally laid down the law about how to deal with the bodies to avoid further infections. Among his specifications—made in “Orders Conceived and Published by the Lord Mayor and Aldermen of the City of London, Concerning the Infection of the Plague”—was that “all the graves shall be at least six feet deep.”

The law eventually fell out of favor both in England and its colonies. Modern American burial laws vary from state to state, though many states simply require a minimum of 18 inches of soil on top of the casket or burial vault (or two feet of soil if the body is not enclosed in anything). Given an 18-inch dirt buffer and the height of the average casket (which appears to be approximately 30 inches), a grave as shallow as four feet would be fine.

A typical modern burial involves a body pumped full of chemical preservatives sealed inside a sturdy metal casket, which is itself sealed inside a steel or cement burial vault. It’s less of a hospitable environment for microbes than the grave used to be. For untypical burials, though—where the body isn’t embalmed, a vault isn’t used, or the casket is wood instead of metal or is foregone entirely—even these less strict burial standards provide a measure of safety and comfort. Without any protection, and subjected to a few years of soil erosion, the bones of the dearly departed could inconveniently and unexpectedly surface or get too close to the living, scaring people and acting as disease vectors. The minimum depth helps keep the dead down where they belong.

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This article originally appeared in 2012.

What's the Difference Between Apple Juice and Apple Cider?


In a time before pumpkin spice went overboard with its marketing, people associated fall with fresh apples. Crisp and fresh, they practically beg to be crushed and pulped into liquid. But what’s the difference between apple juice and apple cider?

According to the state of Massachusetts, home to a variety of apple-picking destinations, both apple juice and apple cider are fruit beverages. But apple cider is raw, unfiltered juice—the pulp and sediment are intact. To make cider, the apples are ground into an applesauce-like consistency, then wrapped in cloth. A machine squeezes the layers and strains out the juice into cold tanks. That’s the cider that ends up on store shelves.

Apple juice, on the other hand, takes things a step further—removing solids and pasteurizing the liquid to lengthen its shelf life. It’s typically sweeter, possibly with added sugar, and may lack the stronger flavor of its relatively unprocessed counterpart. It’s also often lighter in color, since the remaining sediment of cider can give it a cloudy appearance.

But that’s just the Massachusetts standard. Each state allows for a slight variation in what companies are allowed to call apple cider versus apple juice. The cider may be pasteurized, or the cider and juice may actually be more or less identical. One company, Martinelli’s, states in its company FAQ that their two drinks are the same in every way except the label: "Both are 100 percent pure juice from U.S. grown fresh apples. We continue to offer the cider label since some consumers simply prefer the traditional name for apple juice."

The US Apple Association, a nonprofit trade organization that represents growers nationwide, indicates that apple juice can be made from concentrate, which is why you might see water as the first ingredient on the label. Generally, cider is the hard stuff: Crushed apples with minimal processing. Because it can ferment, it's usually found refrigerated. Apple juice can often be found elsewhere in stores, where it can remain stable.

Which you should buy comes down to personal preference. Typically, though, recipes calling for apple cider should use apple cider. Processed juice may be too sweet an ingredient. And you can always try making a pumpkin spice hot apple cider, although we may stop talking to you if you do.

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