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.

11 Things You Might Not Know About Neil Armstrong

NASA/Hulton Archive/Getty Images
NASA/Hulton Archive/Getty Images

No matter where private or government space travel may take us in the future, NASA astronaut Neil Armstrong (1930-2012) will forever have a place as the first human to ever set foot on solid ground outside of our atmosphere. Taking “one small step” onto the Moon on July 20, 1969, he inspired generations of ambitious people to reach for the stars in their own lives. On the 50th anniversary of Apollo 11, we're taking a look back at the life of this American hero.

1. Neil Armstrong knew how to fly before he got a driver's license.

Neil Armstrong poses for a portrait 10 years before the 1969 Apollo mission
NASA/Hulton Archive/Getty Images

Born August 5, 1930 in Wapakoneta, Ohio, Armstrong became preoccupied with aviation early on. At around age 6, his father took him on a ride in a Ford Trimotor airplane, one of the most popular airplanes in the world. By age 15, he had accumulated enough flying lessons to command a cockpit, reportedly before he ever earned his driver’s license. During the Korean War, Armstrong flew 78 combat missions before moving on to the National Advisory Committee for Aeronautics (NACA), the precursor to NASA.

2. Neil Armstrong's famous quote was misheard back on Earth.

When Armstrong and Buzz Aldrin touched down on the Moon, hundreds of millions of television viewers were riveted. Armstrong could be heard saying, “That’s one small step for man, one giant leap for mankind.” But that’s not exactly what he said. According to the astronaut, he was fairly sure he stated, “That’s one small step for a man, one giant leap for mankind.” The “a” may have broken up on transmission or it may have been obscured as a result of his speaking patterns. (According to First Man: The Life of Neil A. Armstrong, Armstrong said, “I’m not particularly articulate. Perhaps it was a suppressed sound that didn’t get picked up by the voice mike. As I have listened to it, it doesn’t sound like there was time for the word to be there. On the other hand, I think that reasonable people will realize that I didn’t intentionally make an inane statement, and certainly the ‘a’ was intended, because that’s the only way the statement makes any sense. So I would hope that history would grant me leeway for dropping the syllable and understand that it was certainly intended, even if it wasn’t said—although it actually might have been.”) Armstrong claimed the statement was spontaneous, but his brother and others have claimed he had written it down prior to the mission.

3. We don't have a really good picture of Neil Armstrong on the Moon.

Buzz Aldrin is seen walking on the moon
NASA/Hulton Archive/Getty Images

One of the most celebrated human achievements of the 20th century came at a time when video and still cameras were readily available—yet there are precious few images of Armstrong actually walking on the surface of the Moon. (One of the most iconic shots, above, is Aldrin; Armstrong only appears as a reflection in his helmet.) The reason, according to Armstrong, is that he really didn’t care and didn’t think to ask Aldrin to snap some photos. “I don't think Buzz had any reason to take my picture, and it never occurred to me that he should,” Armstrong told his biographer, James R. Hansen. “I have always said that Buzz was the far more photogenic of the crew."

4. A door hinge may have made all the difference to the Apollo 11 mission.

Theories abound as to why it was Armstrong and not Buzz Aldrin who first set foot on the Moon. (On the Gemini missions, the co-pilot did the spacewalks, while the commander stayed in the craft. For Apollo 11, Armstrong was the commander.) The answer may have been the simple logistics of getting out of their lunar module. The exit had a right hinge that opened inwardly, with the man sitting on the left (Armstrong) having the most unobstructed path to the outside. Aldrin would have essentially had to climb over Armstrong to get out first.

5. Neil Armstrong was more concerned about landing on the Moon than he was walking on it.

The lunar module that took NASA astronauts to the moon
NASA/Hulton Archive/Getty Images

The romantic notion of a human stepping foot on space soil captured imaginations, but for Armstrong, it was getting there in one piece that was the real accomplishment. The lunar module Armstrong controlled had to be brought down on the Moon’s surface from 50,000 feet up, avoiding rocks, craters, and other obstacles as it jockeyed into a position for landing. Because there is no air resistance, nothing could slow their descent, and they used thrusters to guide the craft down. That meant there was only enough fuel to attempt it once. The “business” of getting down the ladder was, in Armstrong’s view, less significant.

6. Neil Armstrong was carrying a bag worth $1.8 million.

When Armstrong surveyed the surface of the Moon, he collected a bag of dust for NASA scientists to examine. Apollo moon samples are illegal to buy or sell, but that apparently wasn't the case with the “lunar collection bag” Armstrong used to hold the samples. In 2015, the bag was purchased by Chicago resident Nancy Lee Carlson from a government auction site for $995. But its sale was, apparently, an accident: When Carlson sent the bag to NASA to confirm its authenticity, NASA said it was their property and refused to send it back—so Carlson took the agency to court. A judge ruled it belonged to Carlson, and in 2017, she sold the bag for a whopping $1.8 million at a Sotheby’s auction.

7. Neil Armstrong and his fellow Apollo 11 astronauts had to spend three weeks in quarantine.

Richard Nixon greets the returning Apollo 11 astronauts
NASA/Hulton Archive/Getty Images

When Armstrong, Aldrin, and Michael Collins (who remained behind in the command module while the other two touched down on the Moon) returned to Earth and were fetched by the USS Hornet, they got a king’s welcome. The only asterisk: They had to bask in their newfound fame from inside a sealed chamber. All three men were quarantined for three weeks in the event they had picked up any strange space virus. When President Richard Nixon visited, he greeted them through the chamber’s glass window.

8. Neil Armstrong's space suit was made by Playtex.

Yes, the undergarment people. In the early 1960s, NASA doled out contract work for their space suits to government suppliers, but it was Playtex (or more properly the International Latex Corporation) and their understanding of fabrics and seams that led to NASA awarding them responsibility for the Apollo mission suits. Their A7L suit was what Armstrong wore to insulate himself against the harsh void of space when he made his famous touchdown. The astronaut called it “reliable” and even “cuddly.”

9. Neil Armstrong became a university professor.

Newil Armstrong sits behind a desk in 1970
AFP/Getty Images

Following his retirement from NASA in 1971, Armstrong was reticent to remain in the public eye. Demands for his time were everywhere, and he had little ambition to become a walking oral history of his singular achievement. Instead, he accepted a job as a professor of engineering at the University of Cincinnati and remained on the faculty for eight years.

10. Neil Armstrong once sued Hallmark.

Hallmark was forced to defend itself when Armstrong took issue with the company using his name and likeness without permission for a 1994 Christmas ornament. The bulb depicted Armstrong and came with a sound chip that said phrases like, “The Eagle has landed.” The two parties came to an undisclosed but “substantial” settlement in 1995, which was, according to First Man, donated to Purdue University (minus legal fees).

11. Neil Armstrong was a Chrysler pitchman.

Armstrong’s preference to lead a private life continued over the decades, but he did make one notable exception. For a 1979 Super Bowl commercial spot, Armstrong agreed to appear on camera endorsing Chrysler automobiles. Armstrong said he did it because he wanted the struggling U.S. car maker to improve their sales and continue contributing to the domestic economy. The ads never mentioned Armstrong was an astronaut.

Pioneering Heart Surgeon René Favaloro Is Being Honored With a Google Doodle

Dr. René Favaloro (left) pictured with colleague Dr. Mason Sones.
Dr. René Favaloro (left) pictured with colleague Dr. Mason Sones.
The Cleveland Clinic Center for Medical Art & Photography, Wikimedia Commons // CC BY 4.0

Argentinian heart surgeon René Favaloro is the subject of today’s Google Doodle, which features a sketched portrait of the doctor along with an anatomical heart and several medical tools, The Independent reports.

The renowned doctor was born on this day in 1923 in La Plata, the capital of Argentina’s Buenos Aires province, and pursued a degree in medicine at La Plata University. After 12 years as a doctor in La Pampa, where he established the area’s first mobile blood bank, trained nurses, and built his own operating room, Favaloro relocated to the U.S. to specialize in thoracic surgery at the Cleveland Clinic.

In 1967, Favaloro performed coronary bypass surgery on a 51-year-old woman whose right coronary artery was blocked, restricting blood flow to her heart. Coronary bypass surgery involves taking a healthy vein from elsewhere in the body (in this case, Favaloro borrowed from the patient’s leg, but you can also use a vein from the arm or chest), and using it to channel the blood from the artery to the heart, bypassing the blockage. According to the Mayo Clinic, it doesn’t cure whatever heart disease that caused the blocked artery, but it can relieve symptoms like chest pain and shortness of breath, and it gives patients time to make other lifestyle changes to further manage their disease.

Favaloro wasn’t keen on being called the “father” of coronary bypass surgery, but his work brought the procedure to the forefront of the clinical field. He moved back to Argentina in 1971 and launched the Favaloro Foundation to train surgeons and treat a variety of patients from diverse economic backgrounds.

Favaloro died by suicide on July 29, 2000, at the age of 77, by a gunshot wound to the chest. His wife had died several years prior, and his foundation had fallen deeply into debt, which Argentinian hospitals and medical centers declined to help pay, The New York Times reported at the time.

“As a surgeon, Dr. Favaloro will be remembered for his ingenuity and imagination,” his colleague Dr. Denton A. Cooley wrote in a tribute shortly after Favaloro’s death. “But as a man ... he will be remembered for his compassion and selflessness.” Today would have been his 96th birthday.

[h/t The Independent]

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