Putting Animals in Their Place

Animals. They think they're so special. Sure, they can fly, run at incredible speeds, and regenerate body parts, but do they really have to rub their talents in our faces all the time? Well, we at mental_floss have had enough. It's time to put animals in their place. That's right, crocodiles -call us when you learn to chew.

KANGAROOS CAN'T WALK

(Image credit: Flickr user Chris Samuel)

It's no secret that kangaroos come fully loaded with super-strong legs. The marsupial's powerful gait allows the creature to reach speeds of 40 mph over short spans. And it can travel incredible, marathon-length distances at speeds of about 15 miles per hour -that's a four-minute mile! But don't give those legs too much credit -the kangaroo's long, thick tail also plays a significant part. The natural rudder counterbalances the animal's body as it leans forward to cruise the Outback.

Such muscular gifts do come with some disadvantages, though. While the kangaroo's long, flat feet and 3-foot tail are ideal for hopping, the combo is also the reason kangaroos can't walk. The creature's back legs are designed to move in tandem and don't work well independently of one another. That means it's hopping or nothing. The anatomical quirk also prevents the kangaroo from walking backwards. If the creature tried to back up, its thick tail gets in the way. And because those clunky feet have to move in unison, a kangaroo can't maneuver around the appendage.

Not being able to walk may seem limiting, but it's not a bad tradeoff considering the kangaroo lifestyle. The marsupial's unique makeup proves especially helpful when it comes to self-defense; not only can the creatures outrun dingos and other hungry predators, but if cornered, a kangaroo will become incredibly acrobatic, using its large legs to kick while rising up on its tail for balance.

HORSES CAN'T VOMIT

(Image credit: Flickr user Gunnar Þór Gunnarsson)

When humans ingest a harmful substance, the body's natural reaction is to expel the intruding toxin by sending it right back the way it came. Horses don't have that luxury. The shortcoming is due to a strong band of muscle at the entrance to the horse's stomach known as the cardiac sphincter. While the muscle will open up to send food down to the gullet, it won't work in reverse.

People have cardiac sphincters, too, but the human version doesn't have the strength or the discipline of the horse's. If it's up against food poisoning or the flu, it'll give. The equine valve, on the other hand, is so strong that a horse's stomach will usually rupture before the sphincter relents. In such cases, the horse essentially dry heaves until its stomach bursts. And while that seems like a terrible way to die, never having to deal with spit-up does have its advantages. For example, the horse community tends to spend way less on Dramamine than other members of the animal kingdom.

CHEETAHS CAN'T ROAR

(Image credit: Flickr user Aftab Uzzaman)

Cheetahs have an astonishing vocal range. They can purr, growl, snarl, cough, hiss, bleat, and moan. When they're excited or calling to their cubs, cheetahs even "chirrup," a noise that sounds deceptively like a bird. And during mating season, these cats really turn on the charm by wooing potential mates with "stutter barks."

What cheetahs can't do, however, is roar. Lions, tigers, and most other big cats sport a pad of fibro-elastic tissue in a very large vocal fold, which is what enables the MGM lion to introduce motion pictures. Cheetahs, clouded leopards, bobcats, and house cats lack this talent. Roaring felines also have a flexible piece in their hyoid bones (located just above the larynx) not found in their softer-spoken relatives. The missing roar doesn't make the cheetah any less dangerous, though -it can accelerate from 0 to 60 mph in less than three seconds, almost fast enough to outrun its vocal shortcomings. Almost.

CROCODILES CAN'T CHEW

(Image credit: Flickr user Tambako the Jaguar)

Ever wonder why crocodiles are always flashing toothy grins? Perhaps its because they know how superior their jaws are. The smug reptiles can snap their mouths shut with a force of 4,000 pounds per square inch -that's more than 10 times the chomping power of a great white shark! But a crocodile's mouth is more than just a giant clamp. Crocs also use their maws to cool off. If you've ever caught the reptile in what looks like a prolonged yawn, it's actually keeping its mouth open to release heat; sometimes a crocodile will even pant to regulate its body temperature. Even more surprising is the way that male crocs pitch in to help little crocodiles hatch: Both mom and pop tenderly roll their eggs in their mouths until the shells break.

But for all their mouth-based talents, here's one thing you'll never see a crocodile do: chew. Crocs are physically incapable of mastication. Instead of grinding their meals, crocodiles wrench large chunks of flesh out of their victims and swallow the pieces whole. Often, they'll team up to get the job done, with one holding dinner in its jaws while others take turns ripping pieces off. Between the blood, the violence, and the fact that no one bothers to chew, a crocodile dinner party isn't exactly a model of etiquette. But the crocs do share, which should count for something.

AND ONE GROUP OF ANIMALS THAT WALKS ON WATER

(Image credit: Flickr user ChvyGrl)

If a colony of fire ants invades your home, don't bother turning the hose on it. Here's why: When groups of fire ants encounter water, they cling together to form a living life raft. As long as they're with friends, the insects will use their claws, jaws, and adhesive pads on their legs to create a super structure to trap air beneath them. The arrangement is so powerful that it can withstand Amazonian flash floods! And joining in can keep fire ants afloat for months.

But a closer look shows that the survival technique isn't quite as voluntary as it seems: If a rebel ant tries to abandon its position in the float, the other will clamp down and forcibly hold it in place. The reaction may seem cruel, but it's for the ant's own good. Fire ants' bodies are denser than water, so while they float as a group, individually they drown.

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The article above, written by Stacy Conradt, is reprinted with permission from the January-February 2012 issue of mental_floss magazine. Get a subscription to mental_floss and never miss an issue!

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