As a PhD student at Oxford studying mating behaviour, Judy Wearing was suddenly struck by a thought: what was the purpose of pubic hair? The point of armpit hair? The function of each of our body\u2019s furry patches? When the published literature failed to produce satisfying answers, Wearing began her own investigation. Her aim was to shed light on why exactly we evolved these particular patches, with pubic hair the most puzzling of all: was it for warmth, protection \u2026 or something else?<\/p>\n
Wearing is still tangling with those questions, some 30 years after her student days. Now an author and editor (largely in the education sector), she has revisited her fascination with hair in Anxious and Hairy: The Evolution and Culture of Human Hair, exploring its unexpectedly dense and layered place in our history and psyche. Even Wearing was surprised by the places her research on hair took her, and the mysteries that still remain to be solved. \u201cA lot of these questions, no one\u2019s actually looked at,\u201d she says over Zoom. Here is a mere snip of the fascinating facts she\u2019s uncovered about hair.<\/p>\n
Judy Wearing was surprised where her research on hair took her. Photograph: Mike Wing1. Hair originated with giant furry lizards<\/p>\n
Hair, or fur, evolved about 245 million years ago with cynodonts, the warm-blooded reptilian ancestors of all mammals, including humans. They had fur for insulation, preventing heat from escaping their bodies. Fossil evidence of the wolf-like Cynognathus suggests it also had whiskers: super sensitive, tactile hairs that provide valuable sensory input.<\/p>\n
2. Hairy or scaly, we\u2019re made of the same stuff<\/p>\n
You may have heard of the protein keratin, integral to human hair, skin and nails. It\u2019s also the basis for cat claws, bird feathers, sheep wool and much else besides. Hair growth is an evolutionary modification of an ancient skin-development process by which reptiles grow scales, Wearing explains, joining the dots with our reptilian ancestors. \u201cYou can think of hair as kind of long, thin scales, in a way. Both are made of keratin.\u201d<\/p>\n
3. Your crowning glory is a pile-up of dead cells<\/p>\n
Cells called keratinocytes are generated from the very base of the hair root, pushing older cells higher inside the tubular follicle. As they pile up, dead keratin cells fuse into shafts, breaking the skin and becoming visible as hair. Each hair follicle functions like a \u201cmini organ\u201d, Wearing says, with its own set schedule of growth and resting phases.<\/p>\n
4. It\u2019s not just \u2018breast or bottle\u2019<\/p>\n
Like fur, the ability to produce milk is another defining trait of mammals. The two are more closely associated than you may think: mammary glands evolved as an adaptation of certain hair follicle glands. In Australia, the echidna and the platypus (both monotremes) embody the evolutionary path, before it diverged. Though they lay eggs, they also nurse their young via specialised milk-secreting patches of fur on their bellies.<\/p>\n
We\u2019ve got just as many follicles as chimps. Photograph: Alamy5. We are not-so-naked apes \u2026<\/p>\n
Though we might appear wildly less furry than our primate relatives, Homo sapiens have the same number of follicles, found everywhere, in fact, except the palms and soles. \u201cWe have as many hair follicles as chimpanzees: two to four million of them,\u201d Wearing says. The difference is that the majority of human hairs are very thin and fine.<\/p>\n
6. \u2026 and terminally patchy<\/p>\n
These shrunken \u201cvellus\u201d hairs that cover the body are distinct from \u201cterminal\u201d hairs: the thicker, stiffer and more pigmented strands growing in what Wearing terms \u201cstrategic locations\u201d across the human body, such as the eyebrows, armpits and groin. The constellation of these patches is unique to our species, but \u201cthere is logical function\u201d underpinning each one, Wearing says.<\/p>\n
7. The eyes have it<\/p>\n
Eyebrows evolved to protect our eyes and communicate social information. \u201cWhen was the last time you remember flashing your eyebrows? We don\u2019t know we\u2019re doing it, but we\u2019re reading those signals all the time,\u201d she says. There is also a rich history of refining them through beauty practices. Shaping eyebrows to be thinner, as has often been the style for women, gets \u201cinterpreted as submissive and friendlier\u201d, Wearing says. In ancient China, there was a 1,000-year-old tradition of removing all the hairs to paint on an altogether new shape, in painstaking symmetry and often non-natural colours.<\/p>\n
Botox is being studied as a potential treatment for depression. Photograph: Posed by model; Dimensions\/Getty Images8. Botox curbs empathy<\/p>\n
Today, one fashion for brows is to stop them from moving, using Botox to prevent wrinkles. But, as Wearing points out, this has indirect implications for our communication too. Psychologists have found that the popular cosmetic procedure impairs our ability to mimic others\u2019 emotional expressions, which curbs empathy. It sounds dystopian, but \u201cthere might actually be positive consequences\u201d, Wearing adds. Botox is being studied<\/a> as a potential treatment for depression, by interrupting the feedback loop by which we experience and express emotions.<\/p>\n 9. Body odour is a broadcast<\/p>\n \u201cUnderarm and body odour are huge in our social communication,\u201d says Wearing. Our armpit strands are stiffer than those in other places, causing them \u201cto stick out\u201d and broadcast our particular chemical blend. Research suggests we can sniff out not only each other\u2019s genetic differences, but emotional states and even health. This exchange largely happens below our conscious awareness, Wearing says. \u201cMost of us never think, \u2018You smell anxious\u2019 \u2013 but we might think, \u2018You look afraid.\u2019\u201d<\/p>\n 10. What about beards?<\/p>\n Though men and women have the same average number of follicles on their faces, the majority of adult men grow terminal hairs rather than the more typically female peach fuzz. The density is determined by genetic and hormonal differences, with beard and moustache hairs regulated by testosterone and dihydrotestosterone. It is likely that facial hair evolved as a means to compete against sexual rivals and communicate dominance. There is even a suggestion that beards \u2013 thick, strong, oilier hair \u2013 provide some protection to the jaw in the event of a punch-up.<\/p>\n Hair loss can be a source of distress for men. Photograph: Posed by model; agrobacter\/Getty Images11. Balding is not so bad<\/p>\n Hair loss is commonly a source of distress for men, associated with higher rates of anxiety, depression and even suicide. Yet it is a natural and even widespread experience, with more than 70% of Caucasian men experiencing thinning on top (50% by the age of 40). \u201cThere\u2019s this notion that it\u2019s pathological, but there\u2019s nothing wrong with it; it\u2019s exceedingly common and evolved for a reason.\u201d Balding can be considered an expression of masculinity, with hair loss regulated by dihydrotestosterone, the same hormone that regulates the growth of the male genitalia. \u201cIt\u2019s testosterone with a punch,\u201d says Wearing, \u201cand about as male as it gets.\u201d<\/p>\n 12. Hair is a health indicator<\/p>\n In many diverse cultures, long hair in men has been historically associated with strength \u2013 think Samson from the Bible. This isn\u2019t just apocryphal: hair is strongly associated with age and health, among people with the genes to grow it long. It grows longer and faster through adolescence and young adults, then slows from around age 25 by about 0.4cm a year. Hair health can also reflect nutritional deficiency, with a lack of protein, iron and vitamins D and B producing more dull and brittle strands. The association between long, shiny hair and good health may be why some women tend to grow hair faster and lose it more slowly (resulting in generally longer hair) than men: it signals a healthy potential mate. Nowadays, of course, we can fake the effect and achieve sleeker, shinier strands with products.<\/p>\n 13. Hair heals<\/p>\n Hair doesn\u2019t just reflect good health; it also functions a bit like the body\u2019s sticking plaster. Stem cells, found at the base of every follicle, support skin regeneration and repair. \u201cThey\u2019re like mini emergency kits, all over our bodies,\u201d Wearing says.<\/p>\n Styling dates back to the bronze age for women. Photograph: Sergii Kolesnikov\/Getty Images14. Styling has a long history \u2026<\/p>\n Evidence of hair styling in women dates back to the bronze age. \u201cIf you look at the earliest statuettes and human images, You see hairstyles, braids, buns,\u201d says Wearing. \u201cThe ancient Egyptians were just wild about wigs, curls, dyes, extensions.\u201d Throughout history, these went in trends, and took off when commercial styling became big business, from the late 17th century. The enormous \u201cpoufs\u201d favoured by the Parisian upper classes in the time of Marie Antoinette, sometimes reaching as far as 40cm above the scalp, were followed by short layered styles, known as Titus cuts.<\/p>\n 15. \u2026 and not just for the rich<\/p>\n Fourteenth century BCE remains excavated from a cemetery in Egypt show evidence of adornments in working-class people. One woman had 70 extensions in varied colours; another elderly woman had dyed her locks with henna not long before her death. Ramses II, who ruled a century later, also covered his greys. \u201cLike today, everyone was doing it,\u201d Wearing says.<\/p>\n 16. Some gentlemen did prefer blondes<\/p>\n