Some cats are hairless because of natural genetic mutations that disrupt how their bodies produce or maintain fur. These mutations affect the proteins responsible for building hair structure, and they’ve appeared spontaneously in domestic cat populations at least twice in recorded history, on different continents, through completely different genetic pathways. Breeders then selectively bred these cats to establish the hairless lines we see today.
The Gene Behind Hairlessness
The most well-known hairless breed, the Sphynx, carries a mutation in a gene called KRT71, which provides instructions for making a structural protein used in hair follicles. In Sphynx cats, a single change in the gene’s DNA creates a faulty instruction that causes the protein to be cut short, missing the section it needs to link with other proteins and form a functional hair shaft.
Here’s the surprising part: Sphynx cats do actually grow hair. Their follicles produce it, but the hair lacks a properly formed root bulb, so it falls out almost immediately or never anchors firmly in the skin. That’s why many Sphynx cats feel like warm peach fuzz rather than being truly bald. They may have short, fine hair on their nose, ears, toes, and tail, but nothing substantial enough to count as a coat.
This mutation is recessive, meaning a kitten needs to inherit a copy from both parents to be hairless. A cat carrying only one copy will look completely normal but can pass the trait to its offspring.
Not All Hairless Cats Share the Same Mutation
The Donskoy (sometimes called the Don Sphynx or Russian Hairless) looks similar to the Sphynx but is genetically unrelated. This breed traces back to 1987, when a kitten named Varvara in Rostov-on-Don, Russia, began losing her fur due to a completely different mutation linked to a condition called feline ectodermal dysplasia. Unlike the Sphynx gene, the Donskoy gene is dominant. Only one copy is needed for a cat to be hairless, which makes the trait much easier to pass on in breeding.
The Peterbald, another hairless breed, was created by crossing Donskoys with Oriental Shorthairs, so it carries the same dominant mutation. These three breeds (Sphynx, Donskoy, and Peterbald) account for most hairless cats, but their genetics took entirely separate paths to reach a similar result.
How the Modern Sphynx Breed Started
In 1966, a domestic shorthair in Toronto gave birth to a hairless male kitten named Prune. That kitten confirmed the mutation was genetic, but the modern Sphynx breed actually descends from two later lines: a pair of barn cats named Dermis and Epidermis found in Minnesota in 1975, and three stray cats discovered in Toronto in 1978. Breeders crossed these cats with Devon Rex and American Shorthairs to build a healthy gene pool while preserving the hairless trait. The Cat Fanciers’ Association accepted the Sphynx for registration in 1998 and granted it full championship status in 2002.
Life Without Fur Changes Everything
Fur does more for a cat than most people realize, and losing it creates a cascade of practical differences. The most significant is temperature regulation. Without an insulating coat, hairless cats lose body heat much faster than furred cats. To compensate, their metabolism runs considerably higher. Sphynx cats need roughly 25 to 30 percent more calories than a typical domestic cat of the same size, simply to maintain their body temperature. They tend to seek out warm spots obsessively: sunny windowsills, heated blankets, laps, and other pets to curl up against.
Their skin also behaves differently. All cats produce natural oils (sebum) from glands in their skin, but in furred cats those oils are absorbed and distributed along the hair shafts. Hairless cats have nowhere for those oils to go, so the sebum accumulates on their skin, giving them a slightly greasy feel. Most hairless cats need a bath every one to two weeks to prevent buildup, which can clog pores and cause skin irritation. Owners often describe them as surprisingly high-maintenance compared to furred cats, which rarely need bathing at all.
Without hair in the ear canals, wax builds up more quickly and with less natural protection, making hairless cats more prone to ear infections. Regular ear cleaning becomes part of the routine. They’re also more susceptible to periodontal disease, though the connection between hairlessness and dental problems isn’t fully understood.
Sun Exposure Is a Real Risk
Fur acts as a natural sunscreen, and without it, hairless cats are vulnerable to sunburn and solar dermatitis, a skin condition caused by UV exposure. Over time, affected skin can become crusted and ulcerated, and in some cases it progresses to squamous cell carcinoma, a type of skin cancer. Non-pigmented (pale or pink) areas of skin are most at risk, particularly the ears, nose, and eyelids.
If you have a hairless cat, limiting direct sun exposure between 10 a.m. and 4 p.m. is the most effective protection. Window glass blocks some UV but not all of it, and many hairless cats are dedicated sun-seekers. Pet-safe sunscreen exists, but cats tend to lick it off almost immediately, and human sunscreen formulations can contain ingredients toxic to cats.
Heart Disease in Hairless Breeds
Sphynx cats carry a notably high risk of hypertrophic cardiomyopathy, a condition where the heart muscle thickens and becomes less efficient at pumping blood. A study of 55 apparently healthy Sphynx cats in New Zealand found that 40 percent were eventually diagnosed with the condition, with an initial detection rate of about 22 percent that climbed after follow-up screening. Researchers identified a variant in a gene called ALMS1 in nearly 71 percent of the cats studied, though the variant alone didn’t predict which cats would develop the disease.
Sphynx cats also appear predisposed to reduced blood flow in the heart muscle, which can contribute to early death in cats with existing heart disease. This makes regular cardiac screening especially important for the breed. The high prevalence suggests the risk is baked into the breed’s relatively small gene pool rather than being a rare occurrence.
Why the Mutation Keeps Appearing
Spontaneous mutations in hair-related genes aren’t unique to cats. Hairless variants have popped up independently in dogs, rats, mice, and guinea pigs. The KRT71 gene, specifically, is involved in hair structure across many mammal species, and small changes to it can have dramatic visible effects. In the wild, a hairless cat would be at a serious disadvantage, losing heat, getting sunburned, and lacking protection from scratches and bites. These mutations would normally disappear within a generation or two through natural selection. It’s only through deliberate human breeding that the trait has been preserved and amplified into stable breed populations.