Why We Don't Have Fur

By | July 9, 2007

Human beings are unusual creatures in many ways — one distinction that often gets overlooked is that we are land-dwelling mammal that isn’t furry. How did this come about? Scientific American says there are three possible explanations:

  1. We used to be semi-aquatic. This theory imagines our human ancestors foraging for food in shallow water. I thought only nut-cases believed this, but apparently it has been put forth as a serious hypothesis. The idea is that we lost our fur the way dolphins and seals did. There’s not much evidence backing this up, however.

  2. Hairless bodies are a heat adaptation. After moving out of the cool shady trees to the hot savannas, our ancestors quickly lost the fur as a means of adapting to the extreme heat. This would have been a drawback at night, however. Also, you have to wonder why we don’t see other examples of land-based mammals ever making a similar adaptation?

  3. We lost the fur in order to get rid of the accompanying parasites. This one makes sense. Imagine living naked in a world with no showers and the possibility of being infested by tics, chiggers, lice — not just in a few areas of your body, but all over. I would definitely do anything I could to evolve away from that.

The other possibility, listed as likely contributing factor, but not a major cause, of human hairlessness is sexual selection. Since we don’t have examples of other species losing fur to avoid parasites or keep cool — keeping in mind that human beings can build fires and make blankets, cold-weather options not available to other creatures who might have gone in a non-fur direction — I tend to think that sexual selection may have been a pretty significant factor. Early human populations may have decided that lighter coats of fur were more attractive and desirable.

And come to think of it, isn’t that still pretty much the case today? Sure, there are people out there with naturally hairy chests and backs, but an outright preference for such bodies (on either aesthetic or sexual terms) would be — I think — in just about any corner of the world, more in the nature of an exception than the norm. Our hairless bodies might well be our oldest cultural artifact!

  • https://www.blog.speculist.com Stephen Gordon

    Maybe hairlessness is an indirect product of the Ice Age. Let’s say that humanity started the Ice Age relatively hairy.

    Being smart, people used fur (from other animals) and fire to suppliment naturally furry bodies during the worst of the Ice Age. Using clothing and fire would continue even after the world began warming.

    BUT as the need for fur diminished in a warmer world, the selective pressure to grow it would be gone.

    In fact, since growing fur is metabolically expensive, evolutionary pressure would eliminate fur from any animal that doesn’t need it.

    Add the benefits of pest reduction AND perhaps sexual selection, and you got both a stick and a carrot moving us toward hairless bodies.

  • rjschwarz

    I like Stephen’s idea and figure it’s probably right, still…

    There is always the chance we stared off with limited hair. Lack of hair might have forced us to adapt and use our brains more to survive.

  • http://www.acceleratingfuture.com/michael/blog Michael Anissimov

    I’m actually reading “The Aquatic Ape Hypothesis” right now and I have to tell you, there’s a lot more meat to this hypothesis than you might think. When I’m done I’ll give my final verdict on my blog, but seriously – the book presents cogent arguments and I have yet to see a serious, in-depth refutation of the AAH by mainstream science. People are starting to take it somewhat seriously because it has not been definitively knocked down in over 30 years, and if it were flat wrong, it probably would have been already. Not to say that it’s right for sure… just that it shouldn’t be dismissed out of hand, as many mainstream anthropologists unfairly do before even taking a close look at it.

  • http://www.mythusmageopines.com/wp mythusmage

    Take a small child, do a close examination of every square inch of the child’s skin. You will find that the only spots lacking hair are the palms of the hands and the soles of the feet. legs, lap, back, abdomen, arms all have fine, light hair.

    In fact, we have about as much hair as a chimpanzee, only ours is light and fine in contrast to the dark, coarse hair of the chimp. It only looks like we’re hairless.

  • http://triticale.mu.nu triticale

    Better yet, rather than a small child, do a close examination of every square inch of Ron Jeremy’s skin.

  • Phil Bowermaster

    Good oral hygiene and blog reading don’t always mix. Triticale, you just made me spit Listerine all over my monitor.

  • MDarling

    Yikes.
    Good comedy is hard in many ways. This works on many levels.
    RJ is a furry guy.
    We know who RJ is.
    We know he’s furry.
    Phil washes his mouth with listerine while on the web.

  • Phil Bowermaster

    I’m not sure whether that last one is funny. Sad, maybe.

  • http://www.carrollton-dentists.com/ Dentists Carrollton

    This is a very interesting post. Well, it is how human being adapted to our environment. Thanks for posting this.