The 10 Fastest Animals in the World

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iStock

Though humans love to assign superlatives—smartest, fastest, strongest—to the creatures of the animal kingdom, those attributes are, in practice, pretty difficult to measure. There are stories of sailfish traveling at 68 mph, for example, but they date to the 1940s and '50s; since then, scientists have determined that anything faster than 33 mph is likely impossible and would lead to "destructive consequences for fin tissues." Old record breaking numbers might be inflated by everything from high wind speeds to inaccurate methodology—not to mention the difficulty of determining the top speed of animals that may or may not be going full out when measured, or the lack of measuring all animals all the time (which means that there still might be record breakers out there). But of the measurements that have been done—and with those caveats in mind—scientists have determined that these 10 creatures are good candidates for the fastest animals on Earth.

10. QUARTER HORSE // 55 MPH

A tan-colored horse running with its mane flying out behind it.
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At the lower end of the list there are several animals that run around the same speed. One of these is the quarter horse, which is generally faster than its more famous thoroughbred relatives—at least over short distances like a quarter mile. And the differences can be pronounced: One study found that over various races of various distances the quarter horse averaged 45 miles per hour, while the thoroughbred averaged only 35 mph—although the thoroughbred generally ran longer races. More impressively, the quarter horse was able to manage over 55 mph near the end of the race [PDF].

9. SPRINGBOK // 60 MPH

A springbok jumping high above yellow grass.
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According to recent research, the black wildebeest has unusual muscle fibers that allow it to run at high speeds for long distances. It's thought that the springbok—which is related to the wildebeest—may also have these fibers, which allows them to escape predators on the African Savannah.

8. PRONGHORN // APPROXIMATELY 40-62 MPH

A pronghorn running.
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The pronghorn is frequently cited as the second fastest land animal on Earth, although many of those speed estimates are based on studies from the 1940s [PDF], when researchers proposed they could run at around 60 mph. Other observations have put pronghorns running almost seven miles in just 10 minutes, which works out to 40 mph.

7. ANNA'S HUMMINGBIRD // 61 MPH

An Anna's hummingbird in flight.
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This little critter can travel at 61 mph for short distances during mating dives. That fact alone is impressive, but this hummingbird is a good candidate for fastest vertebrate by body lengths per second. According to a 2009 paper, it can reach speeds of 385 body lengths per second (that figure doesn't factor in the avian's .59-inch bill; factoring that in reduces the speed to around 320 bl/s). By comparison, the space shuttle reentering the atmosphere travels at around 207 bl/s. For a blue whale to match this hummingbird's relative speed, it would have to circle the entire planet in about an hour.

6. CHEETAH // 65 MPH

A cheetah running.
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The top speed of a cheetah is extremely difficult to determine. One of the fastest reliable records was obtained by a conservationist and the cheetah he'd raised. He attached some meat behind his vehicle and took off, and the cat gave chase, clocking approximately 64 mph over the trials. Meanwhile, a cheetah from the Cincinnati Zoo managed 61 mph in 2012. But these numbers aren't indicative of wild cheetah speed: When scientists put GPS collars on wild cheetahs, they found that although one reached 59 mph, the average top speed was just 33 mph, because it's easier to maneuver at slower speeds.

5. COMMON SWIFT // 70 MPH

A common swift flying.
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Many sources claim that the fastest bird in level flight is the white-throated needletail, sometimes called the spine-tailed swift. But there's no evidence for the methodology behind determining the record, so it's rarely considered valid. So this spot belongs to another swift: One specimen of common swift was observed flying at almost 70 mph.

4. GRAY-HEADED ALBATROSS // APPROXIMATELY 80 MPH

A gray-headed albatross flying.
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The official Guinness World Record for fastest bird in level flight, however, doesn't go to the common swift. It goes to the gray-headed albatross, specifically one gray-headed albatross that got caught in an Antarctic storm. The paper detailing this record holder explained that "typical air speed of small albatrosses flying with a tail wind is [20±9 miles per hour], that speed being relatively constant with increasing wind force" and noted that the bird seemed to have a 40 to 50 mph tailwind. Audubon summarized this as "the equivalent of avian steroids."

3. HYBOMITRA HINEI WRIGHTI // APPROXIMATELY 90 MPH (WE THINK)

A horse fly sitting on a rock.
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According to an article published in Discover in 2000, an entomologist at the University of Florida attempted to recreate the mating behavior of the Hybomitra hinei wrighti horsefly. Males of this species chase and catch the females, and together they fall to the ground. To simulate this, the researcher fired a plastic pellet from an air rifle; the male horsefly chased the pellet, reaching speeds of at least 90 mph. Since then, little research has been done on the subject, and the result is noted as being "a noteworthy record" in "the unrefereed literature."

2. BRAZILIAN FREE-TAILED BATS // 100 MPH (MAYBE)

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According to a 2016 paper, all seven of the Brazilian free-tailed bats studied traveled faster than 55 mph. Five hit almost 70 mph and one flew 100 miles per hour, making it potentially the fastest flying animal in the world. Some scientists that spoke to New Scientist were skeptical of the record, however, saying that the bats may have had gravity or wind assists, but the authors of the study expressed confidence in their results.

1. PEREGRINE FALCON // 200+ MPH

A peregrine falcon flying.
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It's often said that the peregrine falcon can fly around 200 mph, which isn't the entire story. In level flight, the peregrine falcon is usually thought to max out at 40 to 60 mph—fast, but not ridiculously so. It reaches its top speed by falling in a specialized hunting dive called a stoop.

(This may seem like a bit of a cheat—extreme human skydivers can go considerably faster, and if diving speed for all other creatures were counted, this list would be almost entirely birds. A paper published in 2001 [PDF] looked at several dive speeds of just passerine birds and found a barn swallow that dived at 117 mph, a yellow wagtail diving at 118, and a pied flycatcher diving at 120 mph.)

For years, there was suspicion of this top speed, and in the 1990s, some researchers pegged the birds at a more reasonable stoop speed of 90 miles per hour. It wasn't until the 2000s that a researcher began skydiving with a peregrine falcon. Together they were diving at speeds well in excess of 200 mph. But because this is a dive, the title of fastest animal on Earth is still open to debate.

10 Products for a Better Night's Sleep

Amazon/Comfort Spaces
Amazon/Comfort Spaces

Getting a full eight hours of sleep can be tough these days. If you’re having trouble catching enough Zzzs, consider giving these highly rated and recommended products a try.

1. Everlasting Comfort Pure Memory Foam Knee Pillow; $25

Everlasting Comfort Knee Pillow
Everlasting Comfort/Amazon

For side sleepers, keeping the spine, hips, and legs aligned is key to a good night’s rest—and a pain-free morning after. Everlasting Comfort’s memory foam knee pillow is ergonomically designed to fit between the knees or thighs to ensure proper alignment. One simple but game-changing feature is the removable strap, which you can fasten around one leg; this keeps the pillow in place even as you roll at night, meaning you don’t have to wake up to adjust it (or pick it up from your floor). Reviewers call the pillow “life-changing” and “the best knee pillow I’ve found.” Plus, it comes with two pairs of ear plugs.

Buy it: Amazon

2. Letsfit White Noise Machine; $21

Letsfit White Noise Machine
Letsfit/Amazon

White noise machines: They’re not just for babies! This Letsfit model—which is rated 4.7 out of five with nearly 3500 reviews—has 14 potential sleep soundtracks, including three white noise tracks, to better block out everything from sirens to birds that chirp enthusiastically at dawn (although there’s also a birds track, if that’s your thing). It also has a timer function and a night light.

Buy it: Amazon

3. ECLIPSE Blackout Curtains; $16

Eclipse Black Out Curtains
Eclipse/Amazon

According to the National Sleep Foundation, too much light in a room when you’re trying to snooze is a recipe for sleep disaster. These understated polyester curtains from ECLIPSE block 99 percent of light and reduce noise—plus, they’ll help you save on energy costs. "Our neighbor leaves their backyard light on all night with what I can only guess is the same kind of bulb they use on a train headlight. It shines across their yard, through ours, straight at our bedroom window," one Amazon reviewer who purchased the curtains in black wrote. "These drapes block the light completely."

Buy it: Amazon

4. JALL Wake Up Light Sunrise Alarm Clock; $38

JALL Wake Up Light Sunrise Alarm Clock
JALL/Amazon

Being jarred awake by a blaring alarm clock can set the wrong mood for the rest of your day. Wake up in a more pleasant way with this clock, which gradually lights up between 10 percent and 100 percent in the 30 minutes before your alarm. You can choose between seven different colors and several natural sounds as well as a regular alarm beep, but why would you ever use that? “Since getting this clock my sleep has been much better,” one reviewer reported. “I wake up not feeling tired but refreshed.”

Buy it: Amazon

5. Philips SmartSleep Wake-Up Light; $200

Philips SmartSleep Wake-Up Light
Philips/Amazon

If you’re looking for an alarm clock with even more features, Philips’s SmartSleep Wake-Up Light is smartphone-enabled and equipped with an AmbiTrack sensor, which tracks things like bedroom temperature, humidity, and light levels, then gives recommendations for how you can get a better night’s rest.

Buy it: Amazon

6. Slumber Cloud Stratus Sheet Set; $159

Stratus sheets from Slumber Cloud.
Slumber Cloud

Being too hot or too cold can kill a good night’s sleep. The Good Housekeeping Institute rated these sheets—which are made with Outlast fibers engineered by NASA—as 2020’s best temperature-regulating sheets.

Buy it: SlumberCloud

7. Comfort Space Coolmax Sheet Set; $29-$40

Comfort Spaces Coolmax Sheets
Comfort Spaces/Amazon

If $159 sheets are out of your price range, the GHI recommends these sheets from Comfort Spaces, which are made with moisture-wicking Coolmax microfiber. Depending on the size you need, they range in price from $29 to $40.

Buy it: Amazon

8. Coop Home Goods Eden Memory Foam Pillow; $80

Coop Eden Pillow
Coop Home Goods/Amazon

This pillow—which has a 4.5-star rating on Amazon—is filled with memory foam scraps and microfiber, and comes with an extra half-pound of fill so you can add, or subtract, the amount in the pillow for ultimate comfort. As a bonus, the pillows are hypoallergenic, mite-resistant, and washable.

Buy it: Amazon

9. Baloo Weighted Blanket; $149-$169

Baloo Weighted Blanket
Baloo/Amazon

Though the science is still out on weighted blankets, some people swear by them. Wirecutter named this Baloo blanket the best, not in small part because, unlike many weighted blankets, it’s machine-washable and -dryable. It’s currently available in 12-pound ($149) twin size and 20-pound ($169) queen size. It’s rated 4.7 out of five stars on Amazon, with one reviewer reporting that “when it's spread out over you it just feels like a comfy, snuggly hug for your whole body … I've found it super relaxing for falling asleep the last few nights, and it looks nice on the end of the bed, too.” 

Buy it: Amazon 

10. Philips Smartsleep Snoring Relief Band; $200

Philips SmartSleep Snoring Relief Band
Philips/Amazon

Few things can disturb your slumber—and that of the ones you love—like loudly sawing logs. Philips’s Smartsleep Snoring Relief Band is designed for people who snore when they’re sleeping on their backs, and according to the company, 86 percent of people who used the band reported reduced snoring after a month. The device wraps around the torso and is equipped with a sensor that delivers vibrations if it detects you moving to sleep on your back; those vibrations stop when you roll onto your side. The next day, you can see how many hours you spent in bed, how many of those hours you spent on your back, and your response rate to the vibrations. The sensor has an algorithm that notes your response rate and tweaks the intensity of vibrations based on that. “This device works exactly as advertised,” one Amazon reviewer wrote. “I’d say it’s perfect.”

Buy it: Amazon

This article contains affiliate links to products selected by our editors. Mental Floss may receive a commission for purchases made through these links.

10 Facts About Argentine Ants

A pile of genetically-related Argentine ants
A pile of genetically-related Argentine ants
Marc Matteo, Flickr // CC BY-NC 2.0

A supercolony of invasive Argentine ants (Linepithema humile) stretches for 560 miles beneath California, from San Diego to San Francisco. The billions of Argentine ants are unlike other ants in many ways—and they are virtually indestructible. Along with their supercolonies in Europe, Japan, and Australia, L. humile’s global domination is rivaled only by that of human beings. Here’s what you should know about these prolific pests.

1. Argentine ant colonies are ruled by hundreds of queens.

Most ant colonies revolve around a single queen. Growing much larger than the worker drones, she is programmed to mate as quickly as possible, then to leave her nest of origin and establish a new one. In some species, a single queen can lay millions of eggs in a lifetime, producing an army of worker drones and future queens who will go off to build their own nests. But unlike most ants, Argentines are polygynous: Each nest contains multiple queens. In some, they can form up to 30 percent of the population.

2. Argentine ants move their nests frequently.

Nest types vary from ant species to ant species, but those who live in soil commonly dig tunnels and chambers deep into the earth that will protect the colony throughout the life of the queen. L. humile, though, is transient and ever shifting. Argentine ants frequently pack up their eggs and move the entire colony, queen and all, to a new nest, even when there is no apparent threat. Biologist Deborah Gordon told Ars Technica that the ants typically have 20 to 30 shallow nests at any one time, which can be built up in a matter of just weeks.

3. Argentine ants traveled the U.S. before settling down in California.

Argentine ants arrived in the United States from Northern Argentina in the late 19th century, when the first recorded Argentine ant was found in Louisiana in 1891. Researchers believe that the ants hitched a ride to North America in Argentinian shipments of coffee or sugar off-loaded at the Port of New Orleans. From there, they traveled—most likely by train—across the South and into California. Enticed by the Mediterranean climate, one similar to that of its original home in South America, the ants set up shop. By 1907, they’d displaced local native ants and begun their first steps towards total soil domination along 560 miles of California coastline.

4. California’s Argentine ants are more laid-back than their South American cousins.

In side-by-side comparisons of Argentine ants from their South American homeland and California, researchers have found that those from the West Coast are far more mellow than those from Argentina. In studies, it was typical for two ants from different nests to fight when placed in the same vial in Argentina, but in California, ants from different nests rarely fought, even when they were collected from locations several hundred miles apart.

A DNA study of ants from both locations in 2000 revealed a stark difference. In the ants from Argentina, microsatellites—short, uniquely patterned DNA sequences passed down from generation to generation—had more than twice as much variation as the microsatellites of the Californian ants. When two individuals from different nests in California were placed together, they recognized one another as family. The ants from Argentina didn’t, making them more likely to display territorial aggression.

The difference is rooted in the genetic bottleneck the ants encountered on their arrival to the Golden State over a century ago. According to biologist Neil D. Tsutsui, who conducted the DNA study, the ants in California today are all descendants of that founding colony. “It would be as if all of the people in the United States were descended from the Pilgrims who came here in 1620,” he told the Stanford Report in 2004. Instead of competing with one another, generation after generation has worked together to take out native ants and build an immense California colony.

5. Argentine ants protect other insects in exchange for sweet, sweet honeydew.

Argentine ants
Two Argentine ants share a tiny blob of honeydew.
Davefoc, Wikimedia Commons // CC BY-SA 4.0

Argentine ants love to feed on sweet nectar, but flowers and suburban kitchens aren’t the only source of such desirable foodstuffs. Insects that feed on plant sap, like mealybugs, scales, and aphids, naturally excrete sugar-rich liquid “honeydew” from their butts. To secure a steady flow of the sticky-sweet substance, Argentine ants will fight off the predators of their insect chefs, including soldier beetles and midges. They’ll even relocate their honeydew producers to better food sources or microclimates to get the most they can out of their anal secretions.

6. The California Argetine ant supercolony is one-sixth the size of Southern Europe’s.

The California supercolony, which scientists have named the “Californian large,” is only the second-biggest conglomeration of Argentine ants in the world. The biggest colony is found along Southern Europe’s Mediterranean coast, where it stretches 3700 miles from northern Italy to the Atlantic coast of Spain. The ants, introduced around 80 years ago, now number in the billions. Smaller supercolonies also exist in Japan and Australia.

7. Argentine ants are second only to humans in their scale of world domination.

In 2009, researchers discovered that Argentine ants from three of the world’s largest supercolonies (Southern Europe, California, and Japan) are so closely related that they actually form a single mega-colony. The study, led by Eriki Sunamura from the University of Tokyo, found that when placed together, ants from the three supercolonies refused to fight. Instead, they rubbed antennae in greeting the way L. humile does when interacting with genetically-related individuals.

The researchers believe that the Argentine ant mega-colony isn’t just the largest insect colony ever identified; it rivals that of human colonization around the globe. Presenting their findings in the journal Insect Sociaux, they wrote, “the enormous extent of this population is paralleled only by human society.”

8. A mass execution of Argentine ant queens takes place every spring.

Each spring, just before mating season begins, worker ants go on a killing rampage and assassinate 90 percent of their queens. Entomologists aren’t sure exactly why the large-scale execution occurs, but one hypothesis, published in the Journal of Evolutionary Biology in 2001, suggests that it is a “spiteful behavior” to kill the queens that are less related, on average, to the workers.

In their study, researchers from the University of Lausanne hypothesized that Argentine ants are regularly separated from direct family members through free exchange among the nests. Before mating season begins each year, those that are genetically related band together to kill more distantly related queens. Doing so decreases the nest’s genetic diversity and allows it to be rebuilt with a queen who is directly related to the greatest majority of workers.

The study’s results were inconclusive and the question remained unanswered, yet researchers learned something unexpected in the process. Instead of finding genetic diversity among worker ants, those belonging to each nest were actually a homogenous population. Only the queens were genetic outliers with relatively few familial relationships in each nest.

9. Climate change is making Argentine ants more of a nuisance to humans.

Argentine ants thrive in a Mediterranean climate where winters are cool and wet and summers are warm and dry. When conditions are ideal, they largely keep to themselves, but when conditions are drought-like or extremely wet, the ants move indoors in search of more hospitable climes. Experts at survival, Argentine ants can find food or water that’s been left unguarded in just minutes.

With the climate crisis, conditions in California are becoming more extreme. Hot days, no longer relegated just to the summer months, are becoming more numerous and prolonged. Droughts are becoming more frequent. While these changes are unlikely to harm much of the California supercolony, they are likely to drive the residents of urban nests more frequently into people's homes, making the ants a major nuisance for residents from San Diego to San Francisco.

10. Argentine ants are almost impossible to eradicate.

Individual Argentine ants are easy enough to kill, but an Argentine ant colony is a different story. The California colony has no natural predators and, thanks to their high levels of cooperation and massive numbers, L. humile has effectively destroyed possible competitors and disrupted the ecological balance of native species in the process. Insecticides, which are unable to penetrate into the underground nests, aren’t particularly effective. And because the ants can pick up and move their entire nest so quickly, neither are household control measures such as ant bait. After just over a century in California, Argentine ants are now virtually invincible.