Tuesday, September 27, 2011

photosfromajerk said: Every time I see our ancestors portrayed, I see them either shaved or with a somewhat medium sized beard. Common sense says to me that they'd have mighty long beards. Are there any records of them shaving? If so, during what periods? I understand the assumption during the bronze age and on from there, but what about before that?


The quick answer is that: Yes Neanderthals would have had some serious Viking-warrior beards. Maybe (some/most) prehistoric Homo sapiens might have had intense beards. But it’s pretty equivocal of a maybe for the rest of the Homo species - and we really have no idea what type of beards any earlier species might have had.

Facial hair is a tricky one. Well, actually, body hair is a tricky one - it varies racially, it varies along latitudinal climes, and it leaves no (little) trace in the fossil record.

Plus, its sex-linked trait that expresses sexual dimorphism. (Which is also tricky.) And is managed via hormones. (Triple tricky, when it comes to evolution, because it’s tough to separate from genetics, and we have no DNA samples further back than the Neanderthals, anyway, and it’s probably very plastic - meaning, like skin, it can change very rapidly, over a span of hundreds of years, rather than hundreds of thousands.)

The longer answer is that making an educated guess as to when men got beards (and long beards) means we need to look at why they evolved beards: cold weather and sexual selection.

Assuming that primates, apes, and all-potential-ancestors were pretty hairy (body hair, that is) just like a chimp (perhaps more like a bonobo), right up until they diverged with the hominin-lineage, we assume that they didn’t have facial hair. Arms, legs, head - yes. Face - not so much. At least: probably not above the neck, probably not capable of growing much longer than the hair on your legs.

At some point, hominins became less hairy. (Which means that although we still have just as many potential hair follicles per square inch of skin, those hairs stopped growing. Which means that they stopped expressing. Which means that they stopped getting hormonal signals telling them to grow. Which has a lot to do with genetics, but might also have something to do with diet and development.)

Conventional wisdom says that this (becoming less hairy) happened as part of the response to moving to the savannahs (and out of the forests and woodlands), because of the hotter drier weather. General principle is: the more square inches of skin exposed (and thus able to get sweaty) the better to stay cool in a desert. We know that groups that live in deserts tend to be tall & thin (maximize surface area) whereas groups that that live in cold environments tend to be stocky, robust, and more muscle mass.

Usually, the reconstructions and artists’ illustrations tend assume this hairlessness-change happened to the Homo genus. (Fair guess, since the Homo genus is also defined as becoming taller & thinner with bigger heads - all signs that point to needing to deal with deserts.)

We can guess that beards might have become a serious plus about the same time that clothing became important - and the best evidence for that, so far, is Neanderthals. In other words: when Homo moved into Europe and, because it was so cold, evolved in Neanderthals. (Homo erectus had followed the coastline through the Middle East, India, and into Indonesia a few million years before, but they mostly stayed in warm latitudes and died out before Homo sapiens came looking a couple million years later, so it would be the Homo heidelbergensis that might have been the first guy to really need whiskers who could be our ancestor. Probably.)

At some other point, sexual dimorphism (as measured in over-all body size) decreased drastically. This probably happened at the start of the Homo genus, as well. (Unless it happened twice or more, in steps, or unless it just slowly melted away without any clear change.)

The thing is that although humans have less skeleto-anatomic sexual dimorphism (bone size and shape) than most earlier hominids, we have a great deal of sexually-differential traits. Some of them are functional (mammary glands) and some of them have more to do with signalling and sexual selection (see, again, mammary glands).

Speaking of hair: we don’t know when women developed pubic hair, either. Or when hominin/human women extended their periods’ of fertility, when we stopped displaying obvious signs of estrus, when menstruation developed, when mammary glands became permanently enlarged and always on display. We have a lot of theories - some of which connect some of these things to others - and all of which do a great deal to explain them without saying when. (And, yes, this is related - hang in here with me…)

We often assume that a lot of these changes probably went hand-in-hand with reproductive and developmental changes: female pelvii expanded to allow babies with bigger brains, infants were born less developed with more growing to do outside the body and (most critically) their growth pattern slowed down into segments, adding childhood and adolescence.

(Chimps, all other primates, and most likely most hominids, didn’t have a childhood as we know it. And they never got to be teenagers. Humans grow in spurts and jumps. It’s one of our more unique traits.)

We assume that the change that made our children into children was linked to pair-bonding, monogamy, and changes in social structure. (The theory being that, if a female is going to have a bunch of children hanging around her needing care and attention for a decade, as opposed to three years, she’s going to need some help.) Some prefer to suggest that it went along with a change in diet (because if she didn’t need someone to provide food, she needed some easier and more nutritious and more abundant food-stuff) like meat or shellfish.

There’s a lot of evidence pointing to dietary factors (fatty acids, etc) playing a significant role in brain development and growth. (Such as: you get them, the brain grows; you don’t get them, it doesn’t.)

BUT - these same dietary factors are linked to hormonal factors, which (here it comes) oversee growth and puberty - all of the above being directly linked to (here it comes): Facial hair!

And since we aren’t really sure, yet, when we started having puberty… And, since puberty is mediated by diet and environmental influences… (you see where I’m going with this). It’s tricky.

My guess is that beards are as much a sexually-selective trait as they are an adaptation to cold.

Because growing a long beard, a beard long enough to need to be trimmed or shaved, isn’t necessary to keep a face warm - and it’s a pretty complicated thing. Getting hair to grow long requires a combination of hormonal interactions which have to not only “turn on” the hair follicles on the face to make hair grow there, they have to turn them “extra on” to grow even more.

That “even more” has to do with sexual selection. It happened to women, causing with long hair on our heads. Hair on our heads keeps us warm but there’s no real reason that two feet of hair do a better job at that than 3 inches would do - except that (in most cultures, in most races which have long hair) we find long flowing hair to be sexy and feminine. (And don’t laugh. We find women’s long hair to be so very sexy that all of the major world religions have instituted bans on displaying it: Muslim head-scarves, Catholic nun’s habits, pulling a cloth over your head before entering Jewish or Hindu temples…)

The thing is, most sexually-selected, sexually-differential traits - that is, the things that make men manly and masculine, and women girly and feminine - are some of the most plastic. They change quickly.

So, while it’s easy for me to say that Neanderthals were the first bearded men - for all we know, beards could have come and gone throughout our evolutionary history. They certainly haven’t “stuck” with current Homo sapiens populations, as many Asian, East Asian, African, Indigenous American, & Australian Aborigines don’t grow beards that need to be shaved…

[UPDATE: Not because this post wasn’t long enough already, but because I realized I didn’t answer the question. My bad. I’m blaming my bias against lithics.]

As to any evidence for shaving -

Any stone blade would have made a decent razor. Most stone tools are amazingly sharp, and anything that could skin a deer could shave a man. Stone tools had become formalized and sophisticated in shape long before Homo sapiens…

But whether or not they used them that way… hard to say.

We have no evidence of any form of body modification before Homo sapiens, although our earliest evidence of art itself is usually interpreted as evidence of body modification. (Pieces of red ochre, edges worn from use, are thought to have been commonly used on skin for decoration before they started painting caves.) Shells being pierced to string as a necklace… in terms of cognition, creativity, and brain power: How big of a jump is it from make-up and jewelry to shaving?

I’m not sure - but I’d guess that, while there is no evidence that palaeolithic Homo sapien men did shave, there is as little evidence that they didn’t.

[UPDATE 2: This was all of the top of my head, but it’s gotten me really curious. I’m going to do some research - we’ll see how right I am. I’m pretty certain that nothing I said was wrong, but it’s possible there is some evidence (for hairy-big-beards) or on the origins of shaving that I don’t know about… Genetics, etc. Will do this again soon - and if anyone else knows - please jump in and correct me!]


  1. noellejt posted this