Unraveling the History of Human Hair

iStock/ValuaVitaly
iStock/ValuaVitaly

Be it brown or blond, in a straight or naturally curly hair style, the hair that grows from our heads is a fundamental aspect of the human appearance. Our multitude of hair types is so ubiquitous that it’s actually easy to ignore how weird hair is—and not in the sense that your hair style might be on the wrong side of edgy.

“When it comes to human uniqueness, people come up with all kinds of stuff—culture, intelligence, language,” Tina Lasisi, a doctoral candidate in anthropology at Penn State University, tells Mental Floss. “[But] we’re the only mammals that have hairless bodies and hairy scalps.”

On the surface, our hair types are simple enough. Like fingernails, hair is made mostly of the protein keratin. It can survive for millennia under the right conditions—think Ötzi, the 5300-year-old iceman whose clothing, body, and hair were all preserved when he was frozen in a glacier. In warmer, wetter, more acidic environments, hair can degrade within weeks.

But that’s only what hair is. Why we have different hair types and how they came to be is a mystery that scientists are just now beginning to untangle.

Why Do We Have Hair on Our Heads?

Mother holding child with a braided hairstyle
iStock/Kali9

Some researchers have tried on various hypotheses to explain the patterns of hair growth in Homo sapiens and why they differ so dramatically from our close relatives, like chimpanzees. Losing body hair meant we could sweat more, a cooling mechanism that “helped to make possible the dramatic enlargement of our most temperature-sensitive organ, the brain,” writes anthropologist Nina Jablonski in Scientific American. Other researchers hypothesized that the hair remaining on human heads helped hominins regulate body temperature when they became bipedal and started traveling long distances. Basically, scalp hair created a kind of built-in hat.

Hair doesn’t usually stick around for hundreds of thousands of years the way fossilized bones do. If scientists want to answer the question of how our hair evolved from full-body fur, they have to explore the human genome—and Lasisi found that surprisingly few have done so. That’s partially because of the time and expense of conducting genomic analysis to pinpoint which genes affect the production of hair. But it’s also because it wasn’t a question posed by earlier (male) scientists, according to Lasisi.

“They were like, ‘Oh yeah, hair, it’s sexy on women, it’s probably sexual selection.’ But there was no effort to look into it as a unique human trait because they were more interested in our large brains, bipedalism, and whatnot,” Lasisi says.

How Did Different Hair Types Come To Be?

Blond woman facing forsythia bush
iStock/lprogressman

Even the lack of categorization for hair types is telling. Contrary to what your shampoo bottle may say, there is no real classification system for different hair types. At least not yet.

“Most mammals have straight hair. Only human hair [in African and Melanesian populations] has this tightly coiled configuration. We tend to talk about hair as straight, wavy, curly, in some cases frizzy,” Lasisi says. “But it’s as if we were trying to do genetic studies on height saying, there are short people, medium people, and tall people, now find what genes are related to that.”

In other words, before she could even attempt to answer the question of which genes control the texture and color of hair, Lasisi had to figure out a system for defining those hair textures and colors. Lasisi set about creating a classification system that she eventually hopes to publish, which relies on microscopic analysis of curl radius and measuring precise amounts of melanin in the hair. She then tried to answer the first of many questions: Whether tightly coiled African hair evolved in response to the hot environment. While that research is still ongoing, she says the results may indicate something counterintuitive—the thicker the hair, the better insulator it is from heat.

What's the oldest human hair ever found?

Woman wearing African jewelry viewed from the back
iStock/FernandoPodolski

On the rare occasions when hair is preserved in the fossil record, it can be an incredible source of information about our ancestors’ health and behavior. In 2009, Lucinda Backwell and colleagues described the discovery of what appeared to be human hair in fossilized hyena poop (a.k.a. coprolites) from more than 200,000 years ago—the oldest evidence of human hair to date. Five years later, Backwell and others followed that study with an examination of 48 hairs from hyena coprolites that identified several mammalian species. The presence of all those types of hair mean the hyenas were scavenging from many different remains, including humans.

“In the case of the human hairs in the coprolite, they told us a lot, because there were no bones,” Backwell, an anthropologist with the University of Witwatersrand in South Africa and Instituto Superior des Estudios Sociales, CONICET in Argentina, tells Mental Floss by email. They revealed that humans shared the environment with big herbivores like impala, zebra, kudu, and warthogs in southern Africa 200,000 years ago. Unfortunately for scientists, all of the keratin in that hair sample had been replaced by calcium carbonate that didn’t include any DNA. “The first prize would be to extract DNA and identify whether the hair belonged to a modern or archaic human, or even someone like Homo naledi, with its primitive features and young age,” Backwell said. In addition to helping identify the precise species of hominin, DNA from a hair sample like this could go a long way in telling more about different species’ relationship to one another.

Backwell has also studied human hair found in a high-altitude cave site in Argentina, one of the best environments for preserving hair because it’s “cool, dry, dark, and with a neutral pH,” she says. Like the coprolite hairs in South Africa, dating and identifying hairs in Argentina will help Backwell and others understand the spread of humans across the world.

How Can Hair Shed Light on History?

Woman with brown wavy hair facing the ocean
iStock/lprogressman

When people are exposed to substances in the environment, their hair will retain some of the chemical signatures of those substances. Hair found in ice, in amber, and on mummies from arid regions around the world has allowed researchers to learn fascinating details about the inhabitants of particular regions.

In 2013, archaeologists at the University of Chile analyzed 56 mummy samples found in northern Chile. Using gas chromatography-mass spectrometry (a tool that identifies different substances in a sample—and also happens to be used for drug testing), they found that people had smoked nicotine-containing plants continuously from 100 BCE to 1450 CE. “Overall, these results suggest that consumption of nicotine was performed by members of the society at large, irrespective of their social and wealth status,” the researchers wrote in their study.

Another group of archaeologists collected hair samples from 40 mummies found in Peru, Chile, and Egypt to analyze pre-industrial mercury concentrations across the world, ranging in time from 5000 BCE to 1300 CE [PDF]. Their results, published in 2018, indicated much lower levels of mercury in the environment than in the industrial era. Researchers also discovered that each group’s diet determined the actual level of mercury exposure—the Chilean mummies had higher concentrations from their seafood-based diet, while the Egyptians, who ate land animals, had the lowest.

For now, the mystery of hair’s evolution remains partially unsolved. But the next time you’re at the salon, look in the mirror and remember: Hair is part of what makes us human.

Mapping Technology Reveals 'Lost Cities' on National Geographic

Lin uses his iPad to visualize scanning data of a crusaders' fortress at the lagoon in Acre, Israel.
Lin uses his iPad to visualize scanning data of a crusaders' fortress at the lagoon in Acre, Israel.
Blakeway Productions/National Geographic

Imagine what Pompeii looked like before the lava hit, or Mayan pyramids before the jungle took over. In the past decade, scientists have been able to explore human settlements long since abandoned by using a new wave of accessible technology. Instead of needing an expensive plane and crew to fly aerial sensors, for example, explorers can mount them on cheaper drones and pilot them into previously unreachable areas. The resulting data can tell us more about the past, and the future, than ever before.

That’s the premise of Lost Cities with Albert Lin, a new TV series premiering on National Geographic on Sunday, October 20.

Lin, an engineer and National Geographic Explorer, uses cutting-edge tools to shed light on centuries-old cities in the most beautiful places on Earth. Ground-penetrating radar reveals buried structures without disturbing the landscape. A drone-mounted remote sensing method called LIDAR—short for "Light Detection and Ranging"—shoots lasers at objects to generate data, which Lin visualizes with 3D mapping software. The results suggest what the ruins probably looked like when they were new.

Albert Lin and crew in Peru
Thomas Hardy, Adan Choqque Arce, Joseph Steel, Duncan Lees, Albert Lin, and Alonso Arroyo launch the LIDAR drone at Wat'a in Peru.
National Geographic

“It’s like a window into a world that we’ve never had before,” Lin tells Mental Floss. “It’s shooting millions of laser pulses per second through a distance of air. By digitally removing the top layer of everything above the ground—trees, brush, cacti—you’re washing away the past. All of the sudden you’re left with these fingerprints—experiments in how we organized ourselves through time.”

For the six-episode series, Lin and the expert storytelling team were dispatched to the South Pacific, the Middle East, the Andes, the Arctic, and other destinations. Lin explains that while most of the sites are known to archaeologists, they’ve never been so precisely mapped in three-dimensional detail.

In the first episode, Lin travels to Nan Madol, an enigmatic complex of temples and other structures on the Micronesian island of Pohnpei. With the help of local researchers and indigenous leaders, Lin and the team scan the ruins and digitally erase trees, water, and forest undergrowth to unveil the complex's former grandeur.

“Technology and innovation have always been that gateway to go beyond the threshold, and see what’s around the corner,” Lin says. “Seeing these worlds for the first time since they were left, it’s almost like reversing the burning of the library of Alexandria. We can take the synthesis of knowledge of all these watershed moments of our human journey, and imagine a better future.”

Lost Cities With Albert Lin premieres Sunday, October 20 at 10/9c and resumes on Monday, October 21 at 10/9c on National Geographic.

8 Ways Science Can Boost Your Halloween Fun

iStock
iStock

Halloween is all about embracing the supernatural, but science shouldn't entirely fall by the wayside during the spookiest of holidays. Here are a few ways it can actually improve your holiday, from making trick-or-treating easier to fooling your brain into thinking you're eating tasty treats even though you're nibbling on candy cast-offs.

1. Slow the decomposition of your Halloween jack-o'-lantern.

A Halloween display of five jack-o-lanterns
iStock

You don't have to be an expert gardener to keep your jack-o'-lantern looking fresh all Halloween season long. While scouting out pumpkins, pick hard, unblemished ones and steer clear of those with watery dark spots. These splotches indicate frost damage.

Hold off on carving until right before Halloween so your gourds won't rot—but if you can't resist, try squirting their exteriors with lemon juice after you're done slicing and dicing. The acid inhibits pumpkin enzymes, which react with oxygen and cause browning. A light misting of bleach solution will help keep fungus at bay. Some apply vegetable oil or Vaseline to prevent shriveling and drying. We experimented with various techniques in this video.

For extra TLC, you might even want to bring your jack-o'-lanterns in at night if temperatures dip; if you live in a hot and humid area, extend its life by placing it in the fridge overnight. Try using glow sticks or LED lights instead of flesh-singeing candles.

2. Use apps to plan a treat-or-treating route.

Three children in Halloween costumes trick-or-treating
iStock

Thanks to technology, trick-or-treaters (and their hungry adult companions) can now scout out which neighbors are doling out the best candy and which are sticking with Tootsie Rolls, apples, and toothbrushes. Simply download the app for Nextdoor, the neighborhood-based social network, to check out an interactive "treat map" that lets users tag whether their home is handing out treats, and what that treat is.

Since safety is far more important than sugar, guardians should also consider adding a tracking app to their arsenal come Halloween, especially if their kid's venturing out alone. The Find My Family, Friends, Phone app gives the real-time locations of trick-or-treaters, provides alerts for when they turn home, and also comes with a "panic" button that provides emergency contact details when pressed.

3. Optimize your candy's flavor (even if it's SweeTarts).

Hard candies and gummies strewn across a table
iStock

Not crazy about this year's Halloween loot? Fool yourself into thinking those black licorice pieces and peanut chews taste better than they actually do by eating them after you scarf down the chocolate and Sour Patch Kids. According to a 2012 study published in Psychological Science, being aware that these items of candy are your very last candies actually tricks the brain into appreciating them more (and thus thinking they're tastier than they really are).

Meanwhile, a 2013 study from the same journal found that creating a candy-eating ritual enhances flavor and overall satisfaction. Nibble the ridged edges off a Reese's peanut butter cup before tackling the creamy center, sort the M&Ms by color, and take your time unwrapping a chocolate bar.

4. Create a DIY fog machine with carbon.

Dry ice in a glass bowl
iStock

Save money at Party City by creating your own fog machine at home. When dropped in water, dry ice—or frozen carbon dioxide—creates a gas that's a combination of carbon dioxide and water vapor, but looks like the fog you'd see rolling through a haunted graveyard [PDF].

5. Eat sort-of-heart-healthy Halloween candy.

A stack of dark chocolate chunks on a dark stone background
iStock

Halloween candy isn't always bad for you. While shopping for this year's trick-or-treat bounty, steer clear of sugary confections and milk chocolate mini-bars. Opt for dark chocolate treats instead. Research suggests that our gut microbes ferment the antioxidants and fiber in cocoa, creating heart-healthy anti-inflammatory compounds. Plus, dark chocolate or cocoa also appears to help lower blood pressure for people with hypertension, decrease bad cholesterol, and stave off cardiovascular disease and diabetes, among other benefits.

6. Analyze data on Halloween candy trends and give the people what they want.

Lollipops
5second/iStock via Getty Images

Thanks to data science, you can make sure you're giving out the best treats on the block. Bulk candy retailer CandyStore.com combed through 10 years of data (2007 to 2016, with a particular focus on the months leading up to Halloween) to gauge America's top-selling sweets. They created an interactive map to display their results, which includes the top three most popular Halloween handouts in each state and Washington, D.C. Be prepared for plenty of stoop-side visitors and adorable photo ops.

7. Bake better Halloween treats with chemistry.

Frosted Halloween cookies shaped like ghosts and pumpkins
iStock

Cooking is essentially chemistry—and depending on your technique, you can whip up chewy, fluffy, or decadent Halloween treats according to taste.

Folding chunks of chilled butter into your dough will give you thick, cake-like cookies, as will swapping baking soda for baking powder. When butter melts, its water converts into gas, which leaves lots of tiny holes. If the butter flecks in question are colder and larger, they'll leave bigger air pockets. As for the baking powder, it produces carbon dioxide gas both when it's mixed into the dough and when it's heated. For an extra boost in texture, you can also try adding more flour.

Prefer chewier cookies? Start out with melted butter in the dough, and stick with plain old baking soda.

And for extra-fragrant and flavorful baked goods, opt to use dark sugars—like molasses, honey, and brown sugar—because they're filled with glucose and fructose instead of plain old sucrose. As cookies bake, they undergo two processes: caramelization, in which the sugar crystals liquefy into a brown soup; and the Maillard reaction, a chemical reaction between the dough's proteins and amino acids (flour, egg, etc.) and the reducing sugars that causes tasty browning.

8. Take deep breaths to stay calm in haunted houses.

A brown-haired woman in a red polka dot blouse standing with a frightened expression next to a spider web.
iStock

Halloween can be tough for people with anxiety or low thresholds for fear. While visiting a haunted house or watching a scary movie, remember to take deep breaths, which fends off the body's flight-or-fight response, and reframe your anxiety in your mind as "excitement." It's also a good idea to schedule spine-chilling activities after an activity that triggers feel-good endorphins—say, after a walk to check out your neighbors' awesome Halloween displays.

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