13 Chill Facts About Sloths

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iStock.com/janossygergely

Sloths seem to be everyone's "spirit animal." They get to eat, sleep, and hang out in trees all day, going about their business without a care in the world. Or at least that's how it looks. As it turns out, there are plenty of good reasons why sloths are so sluggish—and laziness isn't one of them. Here are 13 things you should know about the world's slowest animal.

1. TWO-TOED AND THREE-TOED SLOTHS AREN'T ALL THAT SIMILAR.

A baby two-toed sloth
iStock.com/wekeli

The cute little babe pictured above is a two-toed sloth, of which there are two species belonging to the Megalonychidae family. The four species of three-toed sloths, on the other hand, are part of the Bradypodidae family. The two groups are only distant relatives and have a few notable differences between them. While three-toed sloths are active in the daytime, two-toed sloths are nocturnal creatures. Three-toed sloths are also smaller and slower than their two-toed counterparts.

2. BOTH HAVE THREE TOES, THOUGH.

A two-toed sloth
Tim Evanson, Flickr // CC BY-SA 2.0

The names used to distinguish the sloths are somewhat of a misnomer. Both have three toes on each hind limb. The real difference applies to the fingers on their forelimbs; one family has two claws, while the other has three. To avoid confusion, some groups—like The Sloth Conservation Foundation—have starting calling them two-fingered and three-fingered sloths.

3. THEY'RE RELATED TO THE EXTINCT GIANT GROUND SLOTH.

Illustration of a giant sloth
iStock.com/estt

Two-toed and three-toed sloths both evolved from giant ground sloths, the largest of which weighed several tons and stood about 12 feet tall. The animals went extinct about 10,000 years ago, likely due to hunting by early humans.

4. THEY WOULD FAIL AN EYE EXAM.

Close-up of a sloth
iStock.com/BrianLasenby

Sloths aren't exactly known for their sharp senses, and this is especially true for their eyesight. A mama three-toed sloth can't spot her own baby from 5 feet away, and combative male sloths have been observed trying to hit each other from a similar distance. Scientists say a genetic mutation is to blame. Three-toed sloths are born without cone cells in their eyes, which are needed to detect colors. As a result, they see things in black and white, and in poorer resolution, too. They also have a hard time handling bright lights—not the best trait for a diurnal (daytime) creature to have.

5. THEY'RE SURPRISINGLY GOOD SWIMMERS.

Sloths are painfully sluggish on land. Their hind legs are weak, so they have to use their arms and upper body strength to pull themselves forward. Plop them in some water, though, and they can move three times as fast. Their long front arms make them skillful swimmers, and they can hold their breath underwater for up to 40 minutes. If a body of water is nearby, they may jump in and use it as a shortcut to navigate the forest more quickly. In the above clip narrated by David Attenborough, a male sloth swims as fast as he can—which is pretty fast, all things considered—to track down a female sloth's mating call.

6. THEIR "LAZINESS" IS A SURVIVAL TACTIC.

A sloth in a chair
iStock.com/GeorgePeters

It's no secret that sloths are slow. Their reaction time is about a quarter as fast as a human's, and they move at a pace of 6 to 8 feet per minute. Indeed, three-toed sloths are the slowest animals on Earth, beating out other famously slow animals like giant tortoises and snails. When the animals were first documented in 18th-century scientific texts, they were harshly described as "the lowest form of existence." But their slowness is why they haven't died out. Sloths largely subsist on leaves, and it can take up to a month for their four-part stomachs to digest a single meal. The leafy greens aren't very nutritious, so they have to conserve as much energy as possible to survive—and that means moving less. As a bonus, their slow movements help them go unnoticed by predators that rely on sight to hunt down prey, like jaguars, ocelots, and harpy eagles.

7. THEY DO JUST ABOUT EVERYTHING IN TREES …

A baby sloth hangs from a branch
iStock.com/Mark Kostich

Sloths are arboreal creatures, so they spend almost all of their time in trees. They eat, sleep, mate, and give birth while hanging upside-down—a feat made possible by their anatomy. Their internal organs are anchored to their abdomen, which shifts weight away from their diaphragm and lets them breathe more easily, and therefore expend less energy.

Three-inch claws also help them latch onto branches and stay suspended far above the forest floor. In fact, their innate ability to cling to branches is so strong that dead sloths have been found dangling from trees, lending new meaning to the phrase "death grip."

8. … EXCEPT POOP.

A sloth on the ground
iStock.com/Damocean

As a consequence of their slow metabolisms, sloths poop once a week—and sometimes just once a month. Two-toed sloths often let 'er rip from the trees, but three-toed sloths follow a bizarre routine that has baffled scientists. They typically make their way down to the forest floor to relieve their backed-up bowels, and once they get there, they do a little "poo dance" while digging a small hole to defecate inside. Without the camouflage afforded to them by the foliage of the forest canopy, sloths are much more likely to be picked off by predators. About half of all sloth fatalities occur when they're on the ground, most likely doing their business or finishing up. So why do they do it? It might have something to do with sex, and marking a tree for a potential mate to find. "Whatever is going on, it's got to be kind of life or death for survival," sloth biologist Rebecca Cliffe tells The Washington Post. "In my brain, that tells me that it's probably something to do with reproduction because that is the driving fact behind most animals' crazy behaviors."

9. AND THEIR POOPS ARE ENORMOUS.

A man holds a sloth
iStock.com/Ssviluppo

When they do poop, their turds tend to be massive. If you put the contents of a sloth's bowel movement on a scale, they might weigh up to one-third of the animal's body weight. This is 282 percent larger than what scientists would expect to see in an animal of the sloth's size. "You can watch their stomachs physically shrink as they poo," Cliffe tells The Washington Post. Oddly enough, though, sloths don't fart. So there's that.

10. ALGAE OFTEN GROWS ON THEIR FUR.

A sloth covered in algae
iStock.com/dene398

Sloths have a symbiotic relationship with algae. Studies have shown that algae is sometimes passed down from a mother sloth to her baby, and the transfer is mutually beneficial for both animal and plant. The sloth's long fur creates a cozy home for the algae—which readily absorbs the water they need to thrive—and the sloths get a coat of green-tinted fur that doubles as camouflage. Sloths also eat the algae, which provides a much-needed source of nutrients.

11. FEMALE SLOTHS SCREAM WHEN THEY WANT TO MATE.

Females get the courting process started by letting out a loud, high-pitched scream to let male sloths know she's ready to mate. "This call is a loud 'eeeeeh' lasting more or less one second," sloth researcher Adriano Chiarello tells Live Science. Researchers are unsure on the particulars of sloth courting or copulation, or even if males will fight for the right mate with the screeching female (or if any fights are territorial instead). Whatever the details, the ensuing gestation period is between five and six months, and then the female sloth will birth one baby sloth, which is—uninterestingly—just called a baby sloth.

12. THREE-TOED SLOTHS CAN ROTATE THEIR HEADS 270 DEGREES.

A sloth turns its head to look back
iStock.com/MikeLane45

This special talent puts three-toed sloths in the same category as many owls. In both species, this Exorcist-esque ability can be attributed to their bone structure. Sloths have extra vertebrae at the base of their necks that let them look in all directions with ease. Although sloths aren't great at defending themselves, they can at least see when danger is approaching.

13. FOR SUCH DEFENSELESS CREATURES, THEY LIVE FAIRLY LONG LIVES.

A sloth peeks out from behind a tree
iStock.com/Damocean

"Live slow, die whenever"—the unofficial slogan bestowed upon sloths by the internet—pretty much gets it right. On average, sloths live to be about 20 years old, but some species can live longer in captivity. The world's oldest sloth—a female of the Hoffman's two-toed variety named Miss C—died last year at the ripe old age of 43. She was a lifetime resident of Australia's Adelaide Zoo.

11 Facts About French Bulldogs

iStock/carolinemaryan
iStock/carolinemaryan

These cute little dogs are enjoying a serious comeback. Here’s the scoop on the fourth most popular dog breed in America. 

1. FRENCH BULLDOGS HAVE ROOTS IN ENGLAND.


iStock/malrok

The French bulldog’s origins are murky, but most sources trace their roots to English bulldogs. Lace makers in England were drawn to the toy version of the dog and would use the smaller pups as lap warmers while they worked. When the lace industry moved to France, they took their dogs with them. There, the English bulldogs probably bred with terriers to create bouledogues français, or French bulldogs. 

2. THEY WERE BRED TO BE GREAT COMPANIONS.

Frenchies are affectionate, friendly dogs that were bred to be companions. Although they’re somewhat slow to be housebroken, they get along well with other dogs and aren’t big barkers. The dogs don’t need much exercise, so they are fine in small areas and enjoy the safety of a crate.

3. THEY CAN'T SWIM.


iStock/ginastancel

As a result of their squat frame and bulbous head, French bulldogs can’t swim, so pool owners should keep a watchful eye on their pups. Keep in mind that if you plan a beach vacation, your furry friend might feel a little left out. 

4. FLYING IS A PROBLEM FOR THEM, TOO.

French Bulldogs are a brachycephalic breed, meaning they have shorter snouts than other dogs. These pushed-in faces can lead to a variety of breathing problems. This facial structure, coupled with high stress and uncomfortably warm temperatures, can lead to fatal situations for dogs with smaller snouts. Many breeds like bulldogs and pugs have perished while flying, so as a result, many airlines have banned them. 

Luckily there are special airlines just for pets, like Pet Jets. These companies will transport dogs with special needs on their own flights separate from their owners. There's a human on board to take care of any pups that get sick or panic. 

5. THEY MAKE GREAT BABYSITTERS.

When a baby orangutan named Malone was abandoned by his mother, the Twycross Zoo in England didn’t know if he would make it. Luckily, a 9-year-old French bulldog named Bugsy stepped in and took care of the little guy. The pair became fast friends and would even fall asleep together. When Malone was big enough, he joined the other orangutans at the zoo. 

6. THEY'RE SENSITIVE TO CRITICISM.

Frenchies are very sensitive, so they do not take criticism lightly. If you scold a French bulldog, it might take it very seriously and mope around the house. French bulldogs respond better to positive reinforcement and encouragement. 

7. THEY'RE A TALKATIVE BREED. 

French bulldogs might not bark much, but they do like to “talk.” Using a complex system of yawns, yips, and gargles, the dogs can convey the illusion of their own language. Sometimes they will even sing along with you in the car. 

8. THEY HAVE TWO STYLES OF EARS. 


iStock/IvonneW

Originally, French bulldogs had rose-shaped ears, similar to their larger relative, the English bulldog. English breeders much preferred the shape, but American breeders liked the unique bat ears. When a rose-eared bulldog was featured at the Westminster Kennel Club in 1897, American dog fanciers were very angry

9. THIS CONTROVERSY LED TO THE FORMATION OF THE FRENCH BULL DOG CLUB OF AMERICA.

The FBDCA was founded in protest of the rose-shaped ears. The organization threw its first specialty show in 1898 at New York City’s famed Waldorf-Astoria. The FBDCA website described the event: “amid palms, potted plants, rich rugs and soft divans. Hundreds of engraved invitations were sent out and the cream of New York society showed up. And, of course, rose-eared dogs were not welcomed.”

The somewhat catty efforts of the club led to the breed moving away from rose-shaped ears entirely. Today, French bulldogs feature the bat-shaped ears American breeders fought to showcase. 

10. MOST FRENCH BULLDOGS ARE BORN THROUGH ARTIFICIAL INSEMINATION. 

Due to their unusual proportions, the dogs have a little trouble copulating. Males have a hard time reaching the females, and they often get overheated and exhausted when trying to get things going. As a result, a large majority of French bulldogs are created through artificial insemination. While this measure makes each litter of pups more expensive, it also allows breeders to check for potential problems during the process. 

French bulldogs often also have problems giving birth, so many must undergo a C-section. The operation ensures the dog will not have to weather too much stress and prevents future health complications.

11. CELEBRITIES LOVE FRENCHIES.

Frenchies make plenty of appearances in the tabloids. Celebrities like Lady Gaga, Hugh Jackman, and The Rock have all been seen frolicking with their French bulldogs. Even Leonardo DiCaprio has one—aptly named Django. Hugh Jackman’s Frenchie is named Dali, after the way the dog’s mouth curls like the famous artist’s mustache. 

This article originally ran in 2015.

What’s That Thing That Hangs Off a Turkey’s Face?

iStock.com/JZHunt
iStock.com/JZHunt

That thing is called a snood. And it's there to let the other turkeys know that its owner is kind of a big deal.

When a male turkey—known as a tom—wants to mate, he faces two hurdles. One is his potential mates, the female turkeys (a.k.a. hens). In the realm of turkey mating, the hens wield the power of choice and the toms have to get their attention and win the opportunity to reproduce. Come mating season, a tom will strut around, gobble, puff out his chest, fan his tail, and drag his wings to attract the hens, who then pick which of the toms they’ll mate with.

The second problem for a tom looking for love is the other toms in the area. They’re all competing for the same limited number of hens. Sometimes a good mating display isn’t enough to win a mate, and toms will attack and fight each other to secure a hen. 

This is where the snood comes in. That goofy-looking piece of dangling flesh helps a tom both with choosy hens and with competition from rival males. Having a long snood almost always means that a hen will want to mate with him and that another tom will back down from a fight.

DUDES AND THEIR SNOODS

When two toms are trying to establish dominance, they’ll size each other up. Then they'll either fight, or one will flee.

In the late 1990s, Richard Buchholz, an animal behaviorist who focuses on turkeys, wanted to figure out which, if any, characteristics of a tom turkey could predict how they fare in dominance fights. That is, did bigger turkeys tend to win more scuffles? Did older ones? He also wanted to see if the turkeys used any of these predictive cues when sizing each other up. He looked at various characteristics of dominant toms that fight and win, and compared them to those of subordinate toms that lose fights or run from them. Of all the characteristics he looked at, only “relaxed snood length” seemed to be a reliable predictor of how a tom would do in bird-vs-bird combat. The dominant males, the ones who won fights and got a choice mate, had longer snoods.

With that in mind, Buchholz looked at how toms reacted to other toms with snoods of varying sizes. The birds tended to avoid confrontation with other males with longer snoods, and wouldn’t even feed near them. A big snood, this suggests, says to the other turkeys that this is a tom you don’t want to tangle with. Buchholz noted that snood length correlates with age, body mass, and testosterone, so, to competitors, the snood could be a good indicator of a tom’s aggressiveness, age/experience, size, and overall condition and fighting ability.

IN THE SNOOD FOR LOVE

Once the males have established who’s going to have a chance to mate, the final choice goes to the hen. While the mating display is the main draw for getting a hen to check him out, a tom’s snood helps him out again here.

Like it did for the other males, a tom’s snood signals a lot of information to a female assessing potential mates—it indicates how old and how big he is, and even says something about his health. In another study, Buchholz found that longer-snooded toms carried fewer parasites. If a hen wanted to choose a mate with good genes that might help her offspring grow large, live long, and avoid parasites, a tom’s snood is a good advertisement for his genes. In that study, hens showed a clear preference for toms with longer snoods. In another experiment years later, Buchholz found that healthy hens again showed a strong preference for long snoods and that hens with their own parasite problems were less picky about snood length and checked out more potential mates—perhaps, Buchholz thinks, because the hens recognized their own susceptibility to infection and were willing to invest more time searching for a tom with genes for parasite resistance that would complement their own—but still showed some preference for longer ones.

While a snood might look goofy to us, for a turkey, it’s integral to the mating game, signaling to other toms that they should get out of his way and letting hens know that he’s got what they’re looking for.

Have you got a Big Question you'd like us to answer? If so, let us know by emailing us at bigquestions@mentalfloss.com.

An earlier version of this article ran in 2013.

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