Part of the Amazon Thought to Be Uninhabited May Have Been Home to 1 Million People

Aerial photo of site Mt05, a circular enclosure (140 meter diameter) located on a hilltop.
Aerial photo of site Mt05, a circular enclosure (140 meter diameter) located on a hilltop.
José Iriarte

Depictions of the pre-Columbian Amazon basin as dense, inhospitable jungle with just a handful of indigenous communities scattered along the river may need to be updated. According to research published in Nature Communications, there were millions more people living in the rainforest prior to Spanish colonization than previously believed.

The Amazon is the largest rainforest on Earth, which poses a challenge to archaeologists exploring the history of the people who lived there. It's long been assumed that native Amazonians chose to avoid the heart of the forest and instead lived as nomads, never straying far from the major rivers. Some old estimates placed the population of the entire basin between 1.5 and 2 million people.

Thanks to satellites, researchers can now identify traces of long-gone settlements in the less-explored regions of Brazil without having to set foot in the jungle. A team of archaeologists from the University of Exeter used satellite imaging to find geoglyphs—large shapes dug into the ground, possibly for ceremonial purposes—in part of the Brazilian state of Mato Grosso that was thought to be uninhabited.

Geoglyphs and mounded ring villages.
Geoglyphs and mounded ring villages.
Nature Communications, Jonas Gregorio de Souza et al.

After pinpointing the locations of these earthworks, archaeologists visited this section of the southern rim of the Amazon to see some of them in person. At each of the 24 sites they set out to confirm, they found a real-life geoglyph on the ground. At one location, they uncovered charcoal and pottery dating back to 1410 CE. In all, they documented 81 new sites with geoglyphs.

The earthworks would have been carved into the dirt during a seasonal drought, allowing the architects to clear a swath of rainforest. Fortified villages were built in or close to the glyphs, with a network of roads connecting them to each other. The researchers created a computer model that estimated that a 154,000-square-mile patch of land could be home to the remains of 1300 geoglyphs and villages, only two-thirds of which have been discovered. In the late pre-Columbian period, the area, comprising just 7 percent of the Amazon basin, may have sustained a population of 500,000 to 1 million people, according to the researchers' models.

Aerial photo of site ZMt04, which contains the two largest enclosures that were identified.
Aerial photo of site ZMt04, which contains the two largest enclosures that were identified.
José Iriarte

Disease and genocide brought on by the European invasion destroyed most of those settlements, and they were later reclaimed by the rainforest. But evidence of their existence suggests that deforestation and development of the Amazon isn't a new phenomenon.

"Our research shows we need to re-evaluate the history of the Amazon. It certainly wasn't an area populated only near the banks of large rivers, and the people who lived there did change the landscape," researcher José Iriarte said in a statement. "Studies such as ours mean we are gradually piecing together more and more information about the history of the largest rainforest on the planet."

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.

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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.

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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."

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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.

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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.

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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

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This Football-Sized Fossil Egg is the First Found in Antarctica, and It May Have Belonged to a Mosasaur

An artist’s interpretation of the birth of a baby mosasaur.
An artist’s interpretation of the birth of a baby mosasaur.
Francisco Hueichaleo, 2020

In 2011, Chilean scientists discovered a football-sized fossil off the coast of Seymour Island, near the northern tip of the Antarctic Peninsula. Though they didn’t know what it was at the time—and simply called it “The Thing”—new research shows that not only is it the first fossil egg ever found in Antarctica, it’s also the largest soft-shelled egg ever found anywhere.

In a study published today in the science journal Nature, researchers from the University of Texas at Austin and the University of Chile dated the nearshore rock formation where the fossil egg was found to be from the Late Cretaceous period—about 68 million years ago—and measured the fossil itself to be roughly 11.4 inches by 7.9 inches (29 centimeters by 20 centimeters). This empty, partially collapsed egg is smaller only than that of the elephant bird, an extinct, flightless species from Madagascar whose eggs averaged about 12 inches by 8 inches.

giant fossil egg from antarctica
A side view of the fossil egg.
Legendre et al. (2020)

But beyond their size, the eggs don’t have much in common; an elephant bird egg is about five times thicker than this fossil egg, and its hard shell has distinct pores and a prismatic layer that the fossil egg lacks. In other words, an elephant bird egg resembles a giant chicken egg. (And giant is no exaggeration—an elephant bird egg could hold the contents of about 150 chicken eggs.)

elephant bird egg next to a chicken egg
An elephant bird egg next to a chicken egg (and a man's head), to put it in perspective.
Oli Scarff/Getty Images

With its soft shell and oblong shape, the new fossil egg, from the new taxon Antarcticoolithus bradyi, is more similar to a lizard or snake egg, which suggests it could’ve been laid by a large reptile. To test that theory, the researchers compared it to the egg traits of 259 species of lepidosaurs—a subclass of reptile that includes snakes and lizards—and surmised that the egg-layer may have been a marine reptile that measured roughly 23 feet (7 meters) or longer.

The researchers believe this mystery mother might have been a mosasaur, a type of large marine lepidosaur whose remains have also been discovered in the area. During the Late Cretaceous period, mosasaurs were among the most fearsome predators in the ocean. They had strong flippers and sharp teeth, and some species grew as long as 50 feet (though that’s still a good 10 feet shorter than the fictional mosasaur depicted in 2015’s Jurassic World). Fossilized contents of their stomachs show they feasted on a variety of wildlife, including fish, seabirds, turtles, plesiosaurs, and more—one mosasaur had even eaten a few other mosasaurs. And although mosasaurs did live in Antarctica, the continent during the Late Cretaceous period looked nothing like its current frigid landscape.

“Antarctica was rich in life,” Dr. Julia Clarke, a professor in UT Austin’s Department of Geological Sciences and co-author of the study, tells Mental Floss. “Temperate forests diverse in plant species covered exposed land. Giant marine reptiles and much smaller coiled ammonites and relatives of living birds hunted in the seas, while on land, mid-sized non-avian dinosaurs ambled.”

mosasaur birth and egg
The egg looks a lot smaller when you compare it to a full-grown mosasaur.
Francisco Hueichaleo, 2020

Since scientists have uncovered the remains of mosasaurs and plesiosaurs of all ages in the rock formation where the fossil egg was found, some think it may have been a popular place for creatures to hatch and raise their young.

“Many authors have hypothesized that this was sort of a nursery site with shallow protected water, a cove environment where the young ones would have had a quiet setting to grow up,” Lucas Legendre, a postdoctoral researcher and the lead author of the study, said in a press release.

If the fossil egg really did belong to a mosasaur, it could alter our understanding of how mosasaurs gave birth. In South Dakota during the 1990s, scientists unearthed the skeleton of a lizard-like mosasaur called a Plioplatecarpus with five unborn offspring preserved in its abdomen. Because they weren’t in eggs, it was generally thought that mosasaurs gave birth to live young. The existence of Antarcticoolithus bradyi, however, suggests the possibility that some mosasaurs laid soft-shelled eggs that hatched immediately after.

According to Clarke, the discovery of the fossil egg is especially exciting because it demonstrates “how much we have yet to learn about the evolution of eggs, from the first egg-layers that moved away from water to the immense diversity of eggs and reproductive strategies we see today.”