Brain Post: Why Do Humans Have No Fur?

SnowBrains | | BrainsBrains
Creepy, we know.
Creepy, we know.

There are a lot of theories about why humans don’t have any fur.  We’ve narrowed it down to the 3 leading theories for you.

Of the 5,000+ mammal species on Earth, very few are naked.  We are one of them.  The basic reason we have no fur is that it must have been an evolutionary advantage:

“All [no fur theories] 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.” – Mark Page/Scientific American

Is this guy dancing?
Is this guy dancing?

“Why are we the only hairless primate?”

THEORIES BEHIND WHY HUMANS LOST THEIR FUR:

1.  HEAT  THEORY

Africa was hot when we were evolving.  Real hot.  Walking upright got us up and away from the hot soil.  Losing our fur allowed us to lose heat more easily.  Sweating increased evaporative cooling and cooled us down.  Once we got upright and started to walk around in the sunny savannah we were no longer in the cool forest of our ape ancestors and we had to lose the fur to make it easier to rid ourselves heat.

evolution
Monkey to man…

2.  AQUATIC APE THEORY

6-8 million years ago our apelike ancestors lived a semiaquatic lifestyle.  They foraged on foods found in shallow waters.  Hair is a terrible insulator in water, so we lost it as the dolphins and whales did.  (this one kinda sucks to us, it doesn’t have much paleontological support, and just looks at seals and walruses).

Single cell to man
Single-cell to man

3.  PARASITE THEORY

It’s no secret that fur hides ticks, lice, flies, and other nasty ectoparasites.  These creatures aren’t just annoying and blood-sucking, but they bring deadly illnesses like one of the world’s number one killers: malaria.  As human’s brains grew (largely due to the ability to successfully hunt, cook, and eat meat) we became smart enough to make clothes, build shelters, and create fire.  This enabled us to lose the fur to avoid the parasites while being able to stay warm at night with our shelter/fire/clothing combination.

Run from the hair.
Run from the hair.

We know, all of this begs the question:  “Why did we keep the head and pubic hair?”

“Despite exposing us to head lice, humans probably retained head hair for protection from the sun and to provide warmth when the air is cold. Pubic hair may have been retained for its role in enhancing pheromones or the airborne odors of sexual attraction.” – Mark Page/Scientific American

Skull evolution
Skull evolution

Ok, then the final question:  “Why do girls have less hair than boys?”

“Once hairlessness had evolved this way, it may have become subject to sexual selection—being a feature in one sex that appealed to another. Smooth, clear skin may have become a signal of health, like a peacock’s tail, and could explain why women are naturally less hairy than men and why they put more effort into removing body hair.” – Mark Page/Scientific American

Humans make sure that no other fishes will evolve up and conquer us.
Humans make sure that no other fishes will evolve up and conquer us.

The one thing we’d like to point out is that our hair loss could very well have been a combination of the first and third theories above.  Scientists don’t win grants on combining other peoples theories, so it’ll be a while before this is explored.


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10 thoughts on “Brain Post: Why Do Humans Have No Fur?

  1. If humans kept fur, then there would be no fur farms cause it would be useless, and 40 million animals wouldn’t die from fur farms each year.

      1. evolution took milions of years. while at maximum if you manage you will stay with your pety monkey for a hundred year. you better argue basing on scientific proves.

  2. Thought people who were your English and Science teachers?? Proofread and check the longstanding proven facts regarding evolution! As a biology teacher, some of you are very uninformed.

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