Tuesday, November 27, 2012

Yes, North Africa Was The Launch Pad

An essay by Michael Balter in Science asks the question, "Was North Africa the launch pad for modern human migrations?".

This question seems to have an obvious answer. If you're in Africa and thinking about going somewhere else, you're going to have to go through the North part to get anywhere. South Africa seems like a really bad place to look for a "launch pad" of human migrations.


- John Hawks



 

14 comments:

Maju said...

I really hate-hate-hate it when people try see the two sides of the matter... and fail.

What happened with East Africa (which is the real candidate).

And as a matter of fact there are two North Africas: Egypt and NW Africa. Quite neatly separated by a rather vast desertic swath and with rather distinct geographies otherwise (the Nile strip surrounded by deserts vs a rather wide Mediterranean strip between the Atlas and the Sea. In between: the Sahara, almost as much of it as between Morocco and Mali.

How can such a prestigious anthropologis be so dense?

terryt said...

The Sahara has not always been the ' vast desertic swath' and as completely arid as it is today. At times of lessened aridity the 'two Africas', Egypt and NW Africa, would be connected not just with each other but also with East Africa. Anyway Andrew's comment, 'South Africa seems like a really bad place to look for a "launch pad" of human migrations' still stands.

Andrew Oh-Willeke said...

FWIW, the comment is not mine but John Hawks. I quoted him without adding any of my own commentary.

Maju said...

@Andrew: I meant Hawks when I wrote "How can such a prestigious anthropologis[t] be so dense?"

@Terry: true but most of the time it was an arid barrier posing at the least a serious difficulty and most often an almost absolute impossibility of crossing, never mind living in it.

And it is ironic that Hawks does not seem to know that Petraglia in 2007 identified Southern African MSA as the most similar (by far) to the early Indian technologies of Jurreru valley, probably those of our ancestors. But surely they coasted all the way via Zanzibar, you know (boats for the win!)

terryt said...

"true but most of the time it was an arid barrier posing at the least a serious difficulty and most often an almost absolute impossibility of crossing, never mind living in it".

But it only has to be not impassable for only once, and only for the briefest time, for it to be a major route.

"But surely they coasted all the way via Zanzibar, you know (boats for the win!)"

Maju, you know exactly why I believe that to be impossible. And surely if they were capable of using boats to move along the coast all the way from Southern Africa to India we would expect to find evidence of their having formed 'colonies' along the way, especially along the Red Sea coastline. In fact, on the contrary, we find a completely different culture occupying the intermediate region. This huge gap between the South African and Indian representatives is almost certainly the result of the later expansion of the intermediate culture, not a leapfrogging by the South African/Indian culture.

terryt said...

Regarding crossing the Red Sea by boat. I don't know if you've seen this yet, but it looks very much as though at times boats were not needed to cross the Red Sea at all:

http://linearpopulationmodel.blogspot.co.nz/2012/11/understanding-red-sea-response-to-sea.html

Andrew Oh-Willeke said...

The punchline in the Red Sea paper is as follows:

"At the Last Glacial Maximum (LGM), as little as 17 m of water
existed in a 6-km-wide channel at Hanish Sill compared to 137 m of water in a 110-km-wide channel at present[.]" (i.e. at the Southern crossing, rather than the Northern one).

A 17 meter deep straight, even at the lowest tide, still calls for swimming or boating or some kind. If you need to breath air, 4 meters and 137 meters are all the same.

A 6000 meter distance in open waters is more than anyone but a strong swimmer in good physical condition in the prime of life with essentially no baggage could handle without some kind of floatation device. This would have been near the limits of my abilities as a fifteen year old swim team member who practices ten hours a week - the longest swim I've ever done in my life after many years on swim teams was about 5000 meters at one go (and needless to say, when I did it, I wasn't potential shark and alligator bait).

It wouldn't have taken much more than a dead log or two without any maritime workmanship, however, to make the trip much easier and would have taken no navigation skills to speak of during the LGM.

Maju said...

For whatever is worth I totally agree with Andrew. Not just 6 Km is beyond realistic swimming for most healthy sporting people but also a community is only "as strong as its weakest link", as they say and the weakest link is a 2 months old baby, a pregnant woman, a senior member, etc. You can't move a community by mere swimming anywhere: you need boats or rafts where to put the babies and the other stuff.

Terry said:

... "if they were capable of using boats to move along the coast all the way from Southern Africa to India we would expect to find evidence of their having formed 'colonies' along the way"...

Lack of evidence is not evidence of lack: if you don't search for it a lot of stuff just don't show up. Until recently we lacked clear evidence for extrasolar planets or the Higgins Boson but they seem they have been there all the time. I am not aware of any research that really weights against the coastal African canoing hypothesis. Actually we know almost nothing of the archaeology of East Africa outside the too-convenient Rift Valley.

(But we do know of coastal communities in Eritrea before or at the OoA time. Such coastal communities must have got boats of some sort).

And also:

"But it only has to be not impassable for only once, and only for the briefest time, for it to be a major route".

The Sahara was passable once in the Neolithic and it was not such a big impact at either side of it.

terryt said...

"Not just 6 Km is beyond realistic swimming for most healthy sporting people but also a community is only "as strong as its weakest link", as they say and the weakest link is a 2 months old baby, a pregnant woman, a senior member, etc."

But you're basing this whole belief on something that has been in no way proved, that humans crossed the Red Sea from Africa at some time during the Paleolithic. There is in fact no evidence that such a crossing occurred, or even that it is necessary to postulate such a crossing to explain the distribution of human species or even of modern haplogroups. I agree that it seems very likely that a crossing was made towards the end of the Upper Paleolithic, but that was from east to west, into Africa.

"I am not aware of any research that really weights against the coastal African canoing hypothesis".

But there is certainly no evidence 'for' such a hypothesis either. In fact the whole idea was constructed on a faulty construct of the timing of the OoA when it became necessary to come up with some sort of explanation for how humans had moved so rapidly from Africa to Australia. Subsequent research has shown the migration was in fact far from 'rapid'.

Maju said...

Even if people walked all the way to India through the deserts and the mountains, instead of taking the "coastal highway" boats would still be necessary and not just for the sea but for rivers, lakes, etc. Something you almost never do in Africa is to swim because there are crocodiles almost everywhere: boats are instead widespread.

"But there is certainly no evidence 'for' such a hypothesis either".

We have almost identical technology in South Africa and India. We have different technologies in inland East Africa. We have to look precisely at where evidence is missing to provide an explanation and that is the coast (for example).

Which is your explanation for the South Africa - India link demonstrated by Petraglia 2007? It's not enough to deny, you have to propose something better.

terryt said...

"Something you almost never do in Africa is to swim because there are crocodiles almost everywhere: boats are instead widespread".

Widespread today. But from the distribution of haplogroups in Africa it looks very likely that the major rivers were major obstacles during much of prehistory.

"We have almost identical technology in South Africa and India".

So you're claiming that during the Paleolithic a group of people traveled all the way from South Africa to India without popping ashore along the way. To me that seems extremely unlikely to have been the case. Surely the South African and Indian technologies represent survivals of an earlier widespread technology that need not have had used any boats at all.

"We have to look precisely at where evidence is missing to provide an explanation and that is the coast (for example)".

That is your conclusion only because it is your most desired conclusion. Other explanations are obviously possible but you carefully avoid any consideration of such possibilities. The evidence could be 'missing' for any number of reasons.

"Which is your explanation for the South Africa - India link demonstrated by Petraglia 2007? It's not enough to deny, you have to propose something better".

As I suggested above, it presumably represents an ancient connection that goes back beyond the Levant/Arabian Peninsula expansion. However the connection between South Africa/India is by no means limited to just some postulated ocean-voyaging population.

terryt said...

Another quick comment:

"Which is your explanation for the South Africa - India link"

It has long been accepted that cultures, technologies, and even species, at the margins of the geographic distribution maintain earlier versions of what is now found in the centre. For example NZ Maori preserves an early version of Polynesian whereas the language has changed considerably in Central Polynesia. I strongly suspect this is the explanation for what we're seeing in the region between South Africa and India. The South Africa/India culture is an earlier version of the Levant/Arabian culture. It is simply that later changes in the centre failed to reach the margins.

terryt said...

Sorry, me again. This is what John Hawks wrote at the time:

http://johnhawks.net/weblog/reviews/archaeology/middle/petraglia_toba_india_continuity_2007.html

"Based on some features of the tools, Petraglia and colleagues speculate that the makers may have been a relatively early sample of modern humans"

The article itself says:

"these pre- and post-Toba industries suggest closer affinities to African Middle Stone Age traditions (such as Howieson's Poort) than to contemporaneous Eurasian Middle Paleolithic ones that are typically based on discoidal and Levallois techniques"

Back to Hawks:

"A dispersal of MSA people from Africa would be an interesting twist on the 'modern human origins' problem. If the first 'modern' humans outside Africa were MSA users, there is no particular reason to assert that they were different from the population represented at Skhul and Qafzeh. The lack of a full Upper Paleolithic technical kit anywhere in Africa before 50,000 years ago makes an MSA-associated disperal seem more credible. The assembly of the Upper Paleolithic in Eurasia would therefore be a local cultural development, possibly associated with further biological change".

To me the obvious conclusion is that the 'first modern' people out of India are responsible for the similarity between South Africa and India whereas the Upper Paleolithic of Eurasia represents a local development which later expanded through much of the intervening region.

Maju said...

There are no such "earlier versions", otherwise someone would have already pointed us to them. Stop making things up.

MSA and specifically Southern African MSA is what seems to be the matter - of course. Sadly what Hawks could see in 2007 he can't see anymore today it seems.