In Brief. Humans are the only primate species that has mostly naked skin. Loss of fur was an adaptation to changing environmental conditions that forced our ancestors to travel longer distances for food and water. Analyses of fossils and genes hint at when this transformation occurred.
A more widely accepted theory is that, when human ancestors moved from the cool shady forests into the savannah, they developed a new method of thermoregulation. Losing all that fur made it possible for hominins to hunt during the day in the hot grasslands without overheating.
Scientists have suggested three main explanations for why humans lack fur. All revolve around the idea that it may have been advantageous for our evolving lineage to have become less and less hairy during the six million years since we shared a common ancestor with our closest living relative, the chimpanzee.
Some evolutionary psychologists have argued that long head hair improved mating success among ancestral humans by acting as a visible marker of health and hence mate quality (Hinsz et al., 2001; Mesko & Bereczkei, 2004).
It might seem like a deserved nickname; after all, we lack the lush coats of body hair that chimps, bonobos and gorillas have in abundance. But we are not naked. We actually have the same density of body hair as other apes of our size, but ours is largely fine and colourless rather than thick and dark.
As we age, our prolonged exposure to testosterone starts to play a visible role on other body hair as well. Just like it transforms the vellus hair on a young man's face into a thick beard, it also changes the nearly invisible hair that grows in places like our ears into thicker strands.
A new study suggests that an ancient genetic change helps to explain why apes and people do not have tails, but monkeys still do. A team of scientists says it may have pinpointed the genetic mutation that contributed to tail loss.
You see, the women of the Red Yao tribe have some of the longest hair in the world – as in their hair is almost the same length as their height!
This Hadith suggests that the Prophet had long hair on this occasion, because he needed to tidy it up in four plaits.
Religions such as Orthodox Judaism, Rastafarianism, and Sikhism all prohibit haircuts, the removal of facial hair, or a combination of the two due to beliefs that hair is sacred or a gift from God.
H. Harris, publishing in the British Journal of Dermatology in 1947, wrote American Indians have the least body hair, Chinese and black people have little body hair, white people have more body hair than black people and Ainu have the most body hair.
As our prehistoric ancestors moved north, they lost their skin pigmentation to compensate for the diminishing UVB levels that they found at higher latitude. Baldness would have become an advantage due to the greater capacity to synthesise vitamin D in the skin of the bald pate.
Broadly speaking, evolution simply means the gradual change in the genetics of a population over time. From that standpoint, human beings are constantly evolving and will continue to do so long as we continue to successfully reproduce.
It is because of a variant in the EDAR gene, that arose in East Asia about 30,000 years ago. 93% of Han Chinese have this gene variant.
So Jesus, as a philosopher with the "natural" look, might well have had a short beard, like the men depicted on Judaea Capta coinage, but his hair was probably not very long.
However, according to some hadiths regarding the rules of awrah, women are required to grow hair long, long enough that it would cover the breasts or as much awrah parts of the body when they're being buried, because she lacks clothes and long hair would be used as a covering instead.
This is contrary to other Hadiths and to the practice of the Muslims ever since the early days of Islam. The Prophet says: “Whoever has hair should take good care of it.” The length of the beard is not an issue. Those who claim that it should be long do not have any strong evidence to support their view.
Certain races have higher rates of hair loss compared to others. Caucasians have the highest rates out of all the ethnic groups. On the opposite end of the spectrum, Native American Indians, Inuits, and Chinese have the lowest rates.
Caucasian hair is generally straight or wavy and is the thinnest, while its cross-section is relatively elliptic. As for African hair, it is very curly, its thickness is intermediate and the shape of cross-section is highly elliptic.
Asian hair the most dominant hair type in the world out speeds the rest with a growth rate of 1.3cm per month, and despite an estimated 80,000 to 140,000 scalp hairs, it usually has the least density.
Humans and chimps share a surprising 98.8 percent of their DNA. How can we be so similar--and yet so different?
There is nothing new about humans and all other vertebrates having evolved from fish. The conventional understanding has been that certain fish shimmied landwards roughly 370 million years ago as primitive, lizard-like animals known as tetrapods.
Scientists have unraveled the origins of human pregnancy by tracing how our early mammal ancestors first evolved to give birth to live young. They found rogue fragments of DNA that jumped around the genome millions of years ago caused switched off the processes needed to lay eggs.
Like so many things, it comes down to a mixture of genetics and hormones. We know that at least some of the genes for hairiness are carried on the X chromosome – and the way these genes are expressed varies between different men and ethnic groups – but hairiness also correlates with high testosterone levels.
Many hair follicles stop producing new hairs. Men may start showing signs of baldness by the time they are 30 years old. Many men are nearly bald by age 60.