Comments on: On why (some) humans have lost their body hair? Why are we the only hairless primate?

By: Mike Tummon

Mike Tummon — Fri, 30 Dec 2011 05:17:44 +0000

Precicely my thoughts BUT why women selecting men. In primative times men selected their female partner sometimes without consent. I see a preference of less hairy females as being wifes to fight over. And as the generations progressed the outcome was substancial less hair. Pubic hair in a lot of tribal cultures was a signal of breeding age. so it remained in the both sexes
The presence of more hair in mainly european s is largely climatic. Males having full thick beards and sometimes lots of body hair. obviously the females of european stock inherit more body hair because of this.

By: Alessandro

Alessandro — Mon, 24 Oct 2011 22:03:35 +0000

The aquatic theory…. you see that aquatic mammals have more fat and, having humans more underskin fat than other mammals, you think we had an aquatic time in our evolution.
I think we swap cause and effect: water itself doesn’t cause fat growth. The heat transmission in water, the heat you lose, cause you to grow underskin fat.
The lowering of body temperature causes, through selection, a favour for underskin fat.
Now we have hominins without fur; hominins that suffer the cold temperature during the night. They use fire but who camped knows that fire is not always so effective.
So…what is the second choice of a mammal to protect is body against cold temperature after he has lost is fur? underskin fat, also in air environment. It is not water, it is temperature loss that causes underskin fat, don’t you think so?
Do human groups living in artic regions since thousands of years have a higher average level of underkin fat in comparison with tropical humans? This could be a good indication.

By: sayang

sayang — Sat, 22 Oct 2011 19:24:49 +0000

Monkeys have both an under-fur layer and outer “guard hair” fur layer, this is the basic ancestral trait for all mammals (fur + milk nursing = mammal).

Great Apes have lost the inner fur layer due to tree-top nesting in tropical rainforests, where thermal insulation was less significant, but biting insects weren’t (so some apes have thick fur on their more-exposed back but less on their chests (they sleep curled in a ball in the bowl-nest)).

Humans, on the other hand, split from the apes 5,000,000 years ago, with the chromosome #2 translocation, which in my opinion induced altered behavior, by producing a hominin species which spent more time at waterside foraging & bathing and sleeping in inverted bowl-nests on the ground, aka geodesic dome-like huts, waterproof and insect-proof. Thus no selection for fur coat.

DDeden

By: Cathleen

Cathleen — Wed, 19 Oct 2011 02:36:52 +0000

But weren’t the dudes the hunters? Shouldn’t, by that theory, women have more hairiness, not less, then men? So far, I have to think it has to do with being in water.

By: Cathleen

Cathleen — Wed, 19 Oct 2011 02:31:49 +0000

I would think if it evolved because men needed it then women would need it too. No?

By: steve

steve — Sun, 11 Sep 2011 22:06:30 +0000

There are probably a multitude of evolutionary reasons why we grew to have less hair.

I’d imagine that the primary reason was that we became able to insulate ourselves and thus its evolutionary importance was lost.

Assume men are hairier due to spending longer periods working/hunting outdoors, than women so some residual benefit still remained
.

By: Antonio Xeira

Antonio Xeira — Sun, 11 Sep 2011 21:53:17 +0000

And with this comment you will close the discussion!
This argument eases the mind who desnt like to make hard questions, and keep us in ignorance.
Again!

By: DDeden

DDeden — Fri, 02 Sep 2011 19:12:58 +0000

I wrote quite a bit about how ancestral daily semi-aquatic foraging may have produced the mostly hairless condition in humans. There is one additional factor involved, more significant in general hair loss than aquatic foraging. Guess it!

By: Wil

Wil — Sun, 28 Aug 2011 23:25:05 +0000

The most recent view is the naked love theory. Here’s the theory’s abstract:

All primates except human beings have thick coats of body hair. This suggests the primate ancestors of human beings likewise had such body hair and that, for some evolutionary reason, lost their body hair. Various theories have been put forward but none is fully adequate. This article presents the “naked love theory.” This theory locates the origin of human hairlessness in the ancestral mother—infant relationship. In this view, hairlessness is ultimately the adaptive consequence of bipedalism. Because of bipedalism, ancestral infants lost their prehensile feet and thus lost the ability to grasp the mother’s fur with their feet, as do other primate infants. Early bipedal mothers were thus under pressure to carry the infant. Therefore infants survived only if mothers had a strong desire to hold them. Because of the pleasure of skin-to-skin contact, the desire to hold the infant would have been stronger in mothers possessing a hairless mutation that enabled them to give birth to hairless infants. Survival of these infants would have then been greater than that of hair-covered infants. The hairlessness that began to appear in this context of maternal selection was then reinforced by sexual selection in the male—female sexual relationship. This is because a hairless sexual partner would have enabled the hairless individual to recreate the pleasure of skin-to-skin contact in the mother—infant relationship. This theory then helps to explain the evolutionary origins of romantic love.

By: MattR

MattR — Wed, 29 Jun 2011 03:14:02 +0000

Just a thought, but what about fire? When humans “discovered fire”, I’m sure having hand and arm hair didn’t feel too good when singed.