Curly hair doesn’t come from one single ethnicity. It appears across virtually every population on Earth, from sub-Saharan Africa to Southern Europe, the Middle East, South Asia, and the Pacific Islands. In fact, a large DNA-based study found that more than 50% of hair fibers from European, African, and Asian populations (including Middle Eastern groups) show some degree of curl. What differs between ethnic groups is the tightness and pattern of that curl, shaped by thousands of years of evolution, migration, and genetic variation.
Why Humans Evolved Curly Hair
The earliest humans in Africa almost certainly had tightly curled hair, and it wasn’t a coincidence. When early hominids began walking upright, the top of the head became directly exposed to equatorial sun. At the same time, brains were getting larger and generating more metabolic heat. Tightly curled hair solved both problems at once.
A 2024 study published in the journal Temperature found that the helical structure of curly hair creates volume and air pockets above the scalp. This architecture blocks solar radiation from reaching the skin while still allowing heat to escape from the head. Straight hair lying flat against the scalp can trap heat; curly hair acts more like a parasol with built-in ventilation. The researchers concluded that tightly curled scalp hair reduced solar heat gain without requiring extra sweating, which conserved water in hot, arid environments where dehydration could be fatal.
As populations migrated out of Africa into cooler climates over tens of thousands of years, the evolutionary pressure favoring tight curls relaxed. Hair patterns gradually shifted toward wavy and straight textures in regions where retaining body heat mattered more than shedding it. This is the leading explanation for why the tightest curl patterns are most common in populations with deep roots in equatorial Africa, while straighter hair became more prevalent in East Asia and Northern Europe.
How Curly Hair Is Distributed Globally
A multinational study of over 19,000 people, published in Clinical, Cosmetic and Investigational Dermatology in 2025, measured hair curl across ethnic groups. The results challenge the assumption that curly hair “belongs” to any single population. Among people of African ethnicity, about 10.5% reported kinky/coily hair and 12.2% reported curly hair, but a striking 42.9% described their hair as wavy and 31.4% as straight. European respondents showed a nearly identical spread: 12% curly, 41.6% wavy, and 33% straight. Hispanic populations came in at 13.9% curly and 11.5% kinky. Even among Asian respondents, 12.6% had curly hair and 11.4% had kinky hair.
These numbers reveal something important: wavy-to-curly hair is actually the global norm, not the exception. Perfectly straight hair is a minority trait in most populations. The differences between ethnic groups are real, but they’re more about the range and intensity of curl than its presence or absence.
Sub-Saharan Africa
Populations across sub-Saharan Africa display the widest range of tightly coiled hair textures on Earth. This includes everything from loose spirals to very tight z-shaped coils. The tight curl pattern is consistent with the evolutionary pressure of equatorial climates, where passive heat regulation was most critical. African hair also tends to be thicker in diameter, with 40.7% of African respondents in the multinational study reporting thick hair, compared to 26.3% of Asian respondents.
Southern Europe and the Mediterranean
Curly and wavy hair is extremely common around the Mediterranean basin. Genotyping data shows that European hair varies mostly between wavy (46.6%) and straight (40.7%), with about 12.7% curly. Southern Europeans, including Greek, Italian, and Spanish populations, tend to fall on the curlier end of that spectrum. Jewish and Arab populations from the Levant also show high rates of wavy and curly hair, grouped by researchers under “West Asian” hair, which follows a similar distribution to European hair overall.
South and Central Asia
Curly hair appears frequently across South Asia, particularly in populations from southern India, Sri Lanka, and Pakistan. These populations often carry curl patterns ranging from loose waves to tight ringlets, consistent with their proximity to the equator. Central Asian groups tend toward straighter textures.
East Asia
East Asian populations have the highest rates of straight, thick hair, but curly hair still exists. The combined “Asian” category in genotyping studies shows about 46.7% straight and 41.3% wavy hair, with 12% curly. The predominance of straight hair in East Asian populations is linked to specific genetic variations, particularly in the EDAR gene, which influences both hair thickness and texture.
Melanesia and the Pacific Islands
Melanesian populations in Papua New Guinea and the Solomon Islands present a fascinating case. Many individuals have tightly curled or wavy hair combined with naturally blond coloring, a combination found almost nowhere else. Research published in Science identified a single genetic mutation in a gene called TYRP1 as the source of the blond hair, present at a frequency of 26% in the Solomon Islands but completely absent outside Oceania. This mutation evolved independently from the genes responsible for blond hair in Europeans, demonstrating how different populations can arrive at similar visible traits through entirely separate genetic pathways.
The Genetics Behind Curl Pattern
Hair texture is polygenic, meaning dozens of genes contribute to whether your hair is straight, wavy, curly, or coily. No single “curly hair gene” exists. Instead, different populations carry different sets of genetic variants that influence curl. A variation in the TCHH gene is linked to hair texture differences in people of northern European ancestry. Variations in EDAR and FGFR2 affect hair thickness in Asian populations. In people of African descent, the genetic architecture of hair texture involves yet another set of variants, many of which researchers are still identifying.
This means that a person of Irish descent and a person of Nigerian descent can both have curly hair, but the underlying genetic instructions producing those curls are largely different. The physical result looks similar, yet the molecular recipe is distinct.
What Makes Hair Physically Curl
At the structural level, curly hair forms because of an asymmetry inside the hair shaft. The cortex of a hair fiber contains bundles of protein called keratin, packed into structures called macrofibrils. In straight hair, these protein bundles are distributed evenly around a circular cross-section. In curly hair, the cross-section is more elliptical, and the keratin concentrates unevenly, accumulating on the concave (inner) side of the curve.
This asymmetry starts before the hair even leaves the scalp. The precortex cells, which are still developing inside the hair follicle, differentiate unevenly. One side of the developing fiber is denser and stiffer than the other, so as the hair grows out, it bends. The tighter this asymmetry, the tighter the curl. This is why curl pattern is set at the follicle level and can’t be permanently changed by external products.
Hair Classification Systems
The most widely used system for describing curl patterns was developed by Andre Walker, Oprah Winfrey’s longtime hairstylist. It divides hair into four broad types: Type 1 (straight), Type 2 (wavy), Type 3 (curly), and Type 4 (kinky/coily). Each type has three subcategories (a, b, c) that correspond to increasing hair diameter and coarseness.
This system is useful for choosing hair care products, but it doesn’t map neatly onto ethnicity. A person of Somali descent might have Type 3a curls, while a person of Ashkenazi Jewish heritage could have Type 3c. Someone of East Asian ancestry might fall anywhere from Type 1a to Type 2c. The system describes the physical shape of the hair, not its genetic origin, and that’s an important distinction. Curl pattern is one of the most visible human traits, but it’s also one of the least reliable indicators of ancestry.