Is Long Hair only Found in Humans?

Throughout human history, long hair has been a coveted characteristic, perceived as an emblem of beauty, strength, and social status. Most people cannot grow their longer than their mid to lower backs, but there are a few individuals who can grow their hair to the floor. This feature is mostly genetic; the ability to grow very long hair runs in families. Women tend to be better able to grow their hair longer than men, probably due to the differences in hormones where estrogens help keep hair follicles in a growth phase for longer. Though there does seem to be an exception to this rule with American Indians and particularly the Crow Tribe where some men can grow their hair to the ground. In general, beyond ensuring a healthy diet and optimising hair care routines to be gentle on hair, there isn’t much else a person can do to significantly increase the length of their scalp hair.

Until quite recently people (almost exclusively women) could make a quite successful living on the circus and side show circuit displaying their exceptionally long hair. “Madam Milo” toured with Barnum and Baily in the late 1800s. The reason why humans are able grow such long scalp hair is open to question. There doesn’t seem to be any obvious biological advantage to growing hair so long. While it may be important to grow some hair on the scalp to protect the head from sunlight and to keep the brain warm, growing hair beyond shoulder length doesn’t seem to be particularly useful.

It might be that long hair was used as an indicator of health when it came to finding a mate, but more usually, hair coat quality and luster is important in attracting a mate, not so much the length of the hair. Studies on lions and their manes have confirmed this. Females look for healthy manes on males, but apparently mane length is not important. Perhaps as humans had no real predators we had the “luxury” to produce very long hair even though it confers no significant biological advantage.

Long hair isn’t just seen in humans, several animals also flaunt surprisingly long hair:

1. Yaks: This long-haired bovine found in the Himalayas has a dense coat of long hair to protect it from cold temperatures. The hair can extend well below the body and is used by humans for clothing and other textiles.
2. Angora Rabbits: Known for their long, soft, silky wool, these rabbits have some of the longest fur of any rabbit breed.
3. Komondor Dogs: This breed of dog, also known as the “mop dog,” is famous for its distinctive long, corded coat. The Komondor’s fur can grow quite long.
4. Alpacas and Llamas: These animals, native to South America, are known for their long, dense, and warm wool that is often used in textiles.
5. Afghan Hounds: This is a dog breed recognized by its thick, fine, silky coat, coupled with a tail with a ring curl at the end. The breed is selectively bred for its unique features in the cold mountains of Afghanistan.
6. Highland Cattle: These cows are a Scottish breed that have long horns and long wavy coats that are double-layered to protect them from the harsh Scottish weather.
7. Persian Cats: Known for their long, luxurious coats, Persian cats have hair that can become quite lengthy.
8. Merino sheep: These sheep have been specifically bred to produce a long (and fine) wool coat. If it is not shorn regularly the coat builds into an excessive covering. The sheep can end up looking like puff balls on legs if neglected.
9. Angora goats: Also called Ankara goats, they were originally an ancient Turkish breed of domesticated goat, now found in many countries of the world. Angora goats produce the lustrous long fiber known as mohair. The goats are sheared twice a year producing about 5.3 pounds of mohair each time. Their mohair fiber has a staple length of between 12 and 15 cm.

As can be seen, most of these animals are domesticated and specially bred to produce long hair either for esthetic appeal or for practical and commercial use. Several of these long hair breeds are due to intentional selection for a gene mutation in FGF5 which is a well-established regulator of hair growth. Mutations in FGF5 make it non-functional and this can result in much longer time periods of hair growth. FGF5 seems to be an unstable gene as mutations have spontaneously occured in different species and then humans have bred the feature into particular strains of rabbits, dogs, and cats. Mutations in other genes that also control the time period of hair growth cycling probably account for the long hair in angora goats and merino sheep, though the specific genes have not been identified yet.

While is is clear that humans have selected and bred animals with long hair, a naturally long hair coat can be a disadvantage. The hair can cover the eyes and reduce sight. It can overheat the animal in a hot weather zone. Long hair can have a higher level of parasite infestation. It can also be heavy enough to slow the animal down and reduce their chances of escape from their natural predators. Indeed, long hair can make it easier for predators to grab hold and pull down their long haired prey. In the “wild” very long hair is almost exclusively the domain of humans – but not quite.

This is a legend of wild horses in Oregon with exceptionally long manes and tails. Eventually, some of these horses were captured and bred as circus horses. The wild population died out long ago and the captive bred horse lineage also seems to have been lost as the popularity of travelling side shows and circuses has waned. Back in the 1880s though, these horses were a popular show attraction that made a lot of money for their owners. The most famous of the long haired horses was “Linus” (actually there were two linuses) as leaflets and pictures from the nineteenth century show. An article elsewhere on this website tells the story of the long haired Oregon horses.

Long hair in animals and humans remains an intriguing anomaly. Its selective advantage in the wild remains largely unclear. While it may offer no significant biological benefit, its value as a symbol of beauty, health, and uniqueness persists, stirring human curiosity and fascination, from the circus arenas of the past to the present day. It serves as a testament to nature’s uncanny ability to present us with seemingly inexplicable mysteries, like the simple yet perplexing puzzle of very long hair.

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