Prehistoric Human Migrations

[Politesse]

Anything on the Australian Aborigines? They've been there for 60,000 years. Further complicating the matters, they had to reach that island by ocean-worthy boats, something that no other groups of people would accomplish for tens of thousands of years. Then, upon arriving there, they had to lose their nautical knowledge and live lives of utter simplicity. When the Aborigines were discovered by English sailors, they had no words for the concepts of "yesterday" or "tomorrow.".

I realize that this isn't your main point, but this last bit is a common colonialist myth, an urban legend passed around in many different contexts; there were more than 250 languages spoken in pre-colonial Australia, and many of those languages have words for yesterday and tomorrow.
http://itre.cis.upenn.edu/~myl/languagelog/archives/004281.html

And I would challenge "utter simplicity" as well. All cultures must be, and are, as complicated as human life and cognition allow for.

 

[lpetrich]

Here are the winter-solstice day lengths:

• Sintashta (52d N): 7h 30m, 9h 6m, 10h 34m
• Islamabad (34d N): 9h 44m, 10h 49m, 11h 51m
• Karachi (25d N): 10h 27m, 11h 25m, 12h 22m

Using a bit of civil twilight in the days, the nights have lengths

• Sintashta: 16h
• Islamabad: 14h
• Karachi: 13h

Nights are not as impressive as days, since twilight extends into them rather than extending out of them.

In the Indian subcontinent, the Indo-Aryans first reached what is now Pakistan, and then spread out eastward, so I've used Islamabad and Karachi as markers of the northern and southern bounds of their territory.


There is similar evidence of reaching far northern latitudes in Greek mythology. The Laestrygonians of Homer's Odyssey lived in a land of perpetual daylight, as did the Hyperboreans (roughly "beyond the north wind"). I'll use Athens as a reference for Greece and Oslo, Norway as a reference for the Scandinavian fjords.

• Athens (38d N): 14h 38m, 15h 51m, 17h 10m
• Oslo (60d N): 18h 30m, 22h 26m, 24h

Since traveling to the far north is easiest in summer, travelers would notice the long summer days rather than the long winter nights.

 

[rousseau]

Anything on the Australian Aborigines? They've been there for 60,000 years. Further complicating the matters, they had to reach that island by ocean-worthy boats, something that no other groups of people would accomplish for tens of thousands of years. Then, upon arriving there, they had to lose their nautical knowledge and live lives of utter simplicity. When the Aborigines were discovered by English sailors, they had no words for the concepts of "yesterday" or "tomorrow.".

I realize that this isn't your main point, but this last bit is a common colonialist myth, an urban legend passed around in many different contexts; there were more than 250 languages spoken in pre-colonial Australia, and many of those languages have words for yesterday and tomorrow.
http://itre.cis.upenn.edu/~myl/languagelog/archives/004281.html

And I would challenge "utter simplicity" as well. All cultures must be, and are, as complicated as human life and cognition allow for.

Historical thought has a bit of civilizational bias these days.

Even when modern historians choose what to write about the central focus is often on the origins of civilizations. These days this probably has something to do with the inclination of history to follow things with material relevance, but the historical trend was definitely to minimize the significance of hunter-gatherer life.

I would add though that you could call aborigine life simple in the real sense that their societies were literally less complex than some others, you'd just want to avoid using it in a derogatory way.

In the future I think history will start opening itself up to the realization that civilization was basically the result of ecological circumstances in very specific regions, and that there is nothing inherently superior about people who lived in those regions. You could break it down to chemistry, but I won't go there .

 

[Swammerdami]

This is a topic which interests me and about which I have read much, especially as it applies to Europe. Two books I'd recommend are Barry Cunliffe's Europe Between the Oceans and Jean Manco's Ancestral Journeys: The Peopling of Europe. (You'll also want a good book on the Indo-European languages, but I'm so cheap I've never replaced Mallory's 1989 book. Anyway, most of the best information comes from the 'Web.) What is especially intriguing is how the recent boom in DNA testing (especially Y-haplogroups) is advancing knowledge of prehistory so rapidly.

lpetrich makes a good summary, but any brief summary will have over-simplifications. I'll call attention to a few.

While it's generally agreed that proto-Celtic was an Iron Age language, it probably descended from an Indo-European language (call it pre-Celtic) which was dominant in the Bell Beaker phenomenon. There's no proof of this, of course, but I think it's most plausible.

(I don't like to nitpick but languages like Hungarian and Estonian survive in Europe.)

Of recorded non-Indo-European languages in Europe, the only present-day survivor is Basque. From around 500 BCE were Etruscan, in Italy, and Lemnian, in the Aegean island of Lemnos. From around 1000 BCE is Eteocretan and Eteocypriot, known from very fragmentary inscriptions, and from 1500 BCE and earlier, Minoan. Etruscan and Lemnian are likely related, but beyond that, it is hard to discern any relationships. I've seen Basque and Etruscan connected to Hurrian-Urartian and the northern Caucasian languages, but most linguists remain skeptical.

I'm unaware of serious present-day work postulating connections between Etruscan-Lemnian and Basque. (Of course you can find hundreds of unlikely hypotheses in old or non-serious work.) The connections among Basque, Northern Caucasian, along with Burushaski(!) are on much firmer ground. (Hurrian is poorly attested but may be related to Northern Caucasian.) Yes, "most linguists remain skeptical" but most linguists are skeptical of most "lumping" and IMO are usually wrong. These same skeptical linguists also deny the Amerindian hypothesis and Afroasiatic hypothesis. The splitter-vs-lumper debate in historical linguistics would be a topic for another thread.

If you accept the Basque-Caucasian-Burushaski hypothesis, you see a phylum of early farmers' languages now confined to relatively isolated areas. Caucasian remains near the center of the early Neolithic; Basque moved from the Eastern Mediterranean westward with Impressed/Cardial Ware; and Burushaski might be descended from the language of the Indus/Harrapa civilization. (Other, more obvious candidates for the Harappan language fail to fit the clues.)

Etruscan probably arose from a different language phylum in the Eastern Mediterranean, possibly moving to Italy during the "Sea People" era.

The first wave of settlers of our species was the Cro-Magnon people, who arrived around 40,000 years ago. I say our species, because the Neanderthals had already been in Europe for some 100,000 years already. Closely related, but not quite present-day humanity.

But around 30,000 - 20,000 years ago, the continental glaciers went farther south in the Last Glacial Maximum, forcing the Cro-Magnon people southward. When the glaciers retreated, they repopulated northern Europe, coming from the southeast.

The second wave started around 11,500 years ago (11,500 BP or 9,500 BCE), when agriculture was invented in the Fertile Crescent Middle East.

It's misleading to imply that there was a single Paleolithic peopling of Europe. Just looking at the Y-haplogroups found in ancient skeletons, the Aurignacians (Cro-Magnon) were mostly in group C, while the Solutreans were mostly Group I. (And no, I don't intend to imply that there were just two Paleolithic peoplings!)

There's much of interest to say, but let's start here.

 

[James Brown]

Anything on the Australian Aborigines? They've been there for 60,000 years. Further complicating the matters, they had to reach that island by ocean-worthy boats, something that no other groups of people would accomplish for tens of thousands of years. Then, upon arriving there, they had to lose their nautical knowledge and live lives of utter simplicity. When the Aborigines were discovered by English sailors, they had no words for the concepts of "yesterday" or "tomorrow.".

I realize that this isn't your main point, but this last bit is a common colonialist myth, an urban legend passed around in many different contexts; there were more than 250 languages spoken in pre-colonial Australia, and many of those languages have words for yesterday and tomorrow.
http://itre.cis.upenn.edu/~myl/languagelog/archives/004281.html

And I would challenge "utter simplicity" as well. All cultures must be, and are, as complicated as human life and cognition allow for.

I didn't intend to dismiss the Aborgines.

there were more than 250 languages spoken in pre-colonial Australia, and many of those languages have words for yesterday and tomorrow.

Would that mean that "some" of their languages had no words for yesterday or tomorrow?

I only got that factoid from Bill Bryson's In a Sunburned Country. He wrote:

From the first moment of contact the natives were a source of the deepest wonder to the Europeans. When James Cook and his men sailed into Botany Bay they were astonished that most of the Aborigines they saw sitting on the shore or fishing in the shallows from frail bark canoes seemed hardly to notice them...The creaking Endeavour was clearly the largest and most extraordinary structure that could ever have come before them, yet most of the natives merely glanced up and looked at it as if at a passing cloud and returned to their tasks.

They seemed not to perceive the world in the way of other people....They had no chiefs or governing councils, wore no clothes, built no houses or other permanent structures, sowed no crops, herded no animals, made no pottery, possessed almost no sense of property.

Bryson does mention, however, the Aborigines mastery of the continent. "No people on earth have lived in more environments with greater success for longer. It is generally accepted that the Aborigines have the oldest continuously maintained culture in the world. It it thought by some...that the Australian language family may be the world's oldest. Their art and stories and systems of beliefs are indubitably among the oldest on earth.

Sadly, this extraordinary achievement has been largely ignored, even today.

 

[Politesse]

Would that mean that "some" of their languages had no words for yesterday or tomorrow?

No, it means that I don't know 250 languages. The idea that this is actually true is, however, next to inconceivable. And especially since the trope of a native people who "have no concept of time" in one fashion or another is a rumor that has been incorrectly applied to every continent Europe colonized, and it always turns out to be untrue when examined, I'm going to bank on this being one more urban legend even if I don't personally know every language involved.

I love Bill Bryson too, but he is a travel writer, not a researcher. The peoples of Australia had housing and clothing, too, they didn't just freeze in the winter.


Various models of traditional brush housing


Woman and child in a roo-skin cloak, 1872

If it's true that the locals were uninterested in Cook's ship, maybe it's because they'd seen a freaking boat before. He's also wrong that there is an "Australian language family", of any age. In fact, there are twenty-seven, and their relationship is not known, especially a few mysterious isolates that seem unrelated to the others altogether.

 

[bilby]

I didn't intend to dismiss the Aborgines.

there were more than 250 languages spoken in pre-colonial Australia, and many of those languages have words for yesterday and tomorrow.

Would that mean that "some" of their languages had no words for yesterday or tomorrow?

I only got that factoid from Bill Bryson's In a Sunburned Country. He wrote:

From the first moment of contact the natives were a source of the deepest wonder to the Europeans. When James Cook and his men sailed into Botany Bay they were astonished that most of the Aborigines they saw sitting on the shore or fishing in the shallows from frail bark canoes seemed hardly to notice them...The creaking Endeavour was clearly the largest and most extraordinary structure that could ever have come before them, yet most of the natives merely glanced up and looked at it as if at a passing cloud and returned to their tasks.

They seemed not to perceive the world in the way of other people....They had no chiefs or governing councils, wore no clothes, built no houses or other permanent structures, sowed no crops, herded no animals, made no pottery, possessed almost no sense of property.

Bryson does mention, however, the Aborigines mastery of the continent. "No people on earth have lived in more environments with greater success for longer. It is generally accepted that the Aborigines have the oldest continuously maintained culture in the world. It it thought by some...that the Australian language family may be the world's oldest. Their art and stories and systems of beliefs are indubitably among the oldest on earth.

Sadly, this extraordinary achievement has been largely ignored, even today.

That's largely because it isn't there any more. The best and most densely populated parts of the continent are almost entirely devoid of Aborigines; They make up around 3% of the population overall, but are overwhelmingly over-represented in the poorest and least developed places. The biggest populations of Aborigines before the Europeans arrived were in the places the Europeans took over first - Tasmania, and the areas around Port Jackson and Port Phillip (modern day Sydney and Melbourne, respectively). The vast majority of Aboriginal culture as it was at the time of European arrival was destroyed by genocide within a few decades; and much of the rest by forced resettlements, deliberate attempts to eliminate Aboriginal culture and tribal structure (such as the infamous 'Stolen Generations' whereby aboriginal children were taken from their parents to be raised in institutions), and further genocides in the following couple of centuries.

What remains is patchy and broken. A people whose culture was defined by the land to which they belonged, in a continent of hundreds of unique tribes and languages, cannot easily withstand being relocated. Nor can a nomadic lifestyle, in which property is largely meaningless, cope with having a system of universal property ownership imposed, where everything, including the very land itself, is defined by who it belongs to.

It's difficult not to ignore it; The majority of the 'records' existed only in the heads of people who died fighting for their way of life, and what little remains is at the fringes of modern Australian society. The few surviving tribal structures in the red centre likely have little more to tell us about their former coastal relatives than do the suburbanites - most of whom couldn't even tell you which tribe previously occupied the area they now live in - whose neat houses stand on the land they once called home.

 

[aupmanyav]

There is similar evidence of reaching far northern latitudes in Greek mythology. The Laestrygonians of Homer's Odyssey lived in a land of perpetual daylight, as did the Hyperboreans (roughly "beyond the north wind").

वि सूर्यो मध्ये अमुचद रथं दिवो विदद दासय परतिमानमार्यः l
दर्ळानि पिप्रोरसुरस्य मायिन इन्द्रो व्यास्यच्चक्रवान रजिश्वना ll
vi sūryo madhye amucada rathaṃ divo vidada dāsaya pratimānamāryaḥ l
dṛḷāni piprorasurasya māyina indro vyāsyaccakṛvāna ṛjiśvanā ll

In the mid-way of heaven the Sun unyoked his car, the Ārya found a match to meet his damn foe.
Associating with Ṛjiśvan (the sun), Indra overthrew the solid forts of Pipru, conjuring Asura*.
http://sacred-texts.com/hin/rigveda/rv10138.htm

The Asuras abducted the sun and keet it in a dungeon, so the night is extended and spring is delayed. It is Indra and his associates who will deliver the sun from captivity.

"The sun unyoked his chariot in the middle of the sky". Remained in the sky for days together. If it is not a description of Arctic regions (Asia or Europe, whatever), then what is it?

Hindus are fortunate as the history of one merged section of the population still survives in RigVeda and other such books.

 

[lpetrich]

Now for a bit about genetics. Human genetic material is packaged in 23 pairs of chromosomes. All but one pair are "autosomes", inherited from both sexes. Chromosomes can exchange genetic material, thus doing recombination. This can make autosomes difficult to use for tracking ancestry, since autosomes become very mixed over the generations.

However, only part of the Y chromosomes recombines with X chromosomes, and those non-recombining parts are useful for tracking male ancestry.

Our cells have lots of internal structures or "organelles", and among them are mitochondria, with their own genomes, though very vestigial ones. But it is enough to track their ancestry, and since mitochondria are inherited almost exclusively in the female line, their genomes are useful for tracking female ancestry.

 Mitochondrial Eve was a woman whose mitochondria were the ancestors of all present-day human ones, and whose daughters formed the earliest branches in the mitochondrion family tree. She likely lived in East Africa.

 Y-chromosomal Adam was a man whose Y chromosomes were the ancestrors of all present-day human ones, and whose sons formed the earliest branches in the Y-chromosome family tree. He likely lived in West Africa.

Their dating is a very hazy subject, with estimates jumping around quite a bit. But 100,000 - 300,000 years ago is a good consensus estimate.

Mitochondrial Eve was almost certainly not the only woman in her time, and Y-chromosomal Adam not the only man. They may never have met, and they may have lived several thousand years apart. Research into possible human genetic bottlenecks suggests that some early-modern-human populations may have dropped as low as a few thousand over several thousand years. This could have happened around 70,000 years ago as a result of a very big volcanic eruption, but that is something that is argued over a lot ( Toba catastrophe theory).

 

[lpetrich]

Here are Wikpedia's diagrams of early human migrations:
File:Map-of-human-migrations.jpg - Wikipedia
File:Human migration out of Africa.png - Wikipedia
File:Human migrations and mitochondrial haplogroups.PNG - Wikipedia
File:Migraciones humanas en haplogrupos de ADN-Y.PNG - Wikipedia
File:World Map of Y-DNA Haplogroups.png - Wikipedia
Fileeopling of eurasia.jpg - Wikipedia
File:Spread and evolution of Denisovans.jpg - Wikipedia

Here's an overall picture. The present human species originated in Africa, likely central Africa. The first group to split off was the Khoisan people of southern and eastern Africa, and the second group the Pygmies, the short people of the central African forests. These splits happened some 200,000 - 100,000 years ago.

Then around 100,000 years ago, some population split off and departed from Africa. They went on either the north coast or the south coast of the Arabian Peninsula, arriving in what is now Iran. When they got there, they interbred with some Neanderthals.

An offshoot population moved west into Europe some 40,000 years ago, and another offshoot population moved southeast into the Indian subcontinent, and then into southeast Asia, and then into Australia and New Guinea around 60,000 years ago after interbreeding with some Denisovans. An offshoot of southeast Asia moved north into east Asia. Yet another Iranian offshoot moved into central Asia.

From east Asia and central Asia, some populations moved into Beringia and then into the Americas, going southward along the west coast and also spreading eastward as they went.

 Archaic human admixture with modern humans, like Neanderthals and Denisovans

 

[Politesse]

Now for a bit about genetics. Human genetic material is packaged in 23 pairs of chromosomes. All but one pair are "autosomes", inherited from both sexes. Chromosomes can exchange genetic material, thus doing recombination. This can make autosomes difficult to use for tracking ancestry, since autosomes become very mixed over the generations.

However, only part of the Y chromosomes recombines with X chromosomes, and those non-recombining parts are useful for tracking male ancestry.

Our cells have lots of internal structures or "organelles", and among them are mitochondria, with their own genomes, though very vestigial ones. But it is enough to track their ancestry, and since mitochondria are inherited almost exclusively in the female line, their genomes are useful for tracking female ancestry.

 Mitochondrial Eve was a woman whose mitochondria were the ancestors of all present-day human ones, and whose daughters formed the earliest branches in the mitochondrion family tree. She likely lived in East Africa.

 Y-chromosomal Adam was a man whose Y chromosomes were the ancestrors of all present-day human ones, and whose sons formed the earliest branches in the Y-chromosome family tree. He likely lived in West Africa.

Their dating is a very hazy subject, with estimates jumping around quite a bit. But 100,000 - 300,000 years ago is a good consensus estimate.

Mitochondrial Eve was almost certainly not the only woman in her time, and Y-chromosomal Adam not the only man. They may never have met, and they may have lived several thousand years apart. Research into possible human genetic bottlenecks suggests that some early-modern-human populations may have dropped as low as a few thousand over several thousand years. This could have happened around 70,000 years ago as a result of a very big volcanic eruption, but that is something that is argued over a lot ( Toba catastrophe theory).

This is some fuzzy language. The media have hyped the whole idea of a mitochondrial eve, personifying them with religious overtones. There's nothing special about Eve, except that she happens to be the theoretical oldest relative still related to the lot of us by the particular measure of MtDNA. There have been a nmumber of different Eves, depending on what point you wanted to figure from.

 

[Swammerdami]

Some quick corrections:

Autosomal DNA is more useful than sex-linked DNA for tracking ancestry: it can point to all 32 of your gt-gt-gt grandparents, not just two of them. Rather than matching SNP's, cousin-finding software looks for long matching chains. The parameters of chromosome crossover (remember discussion of meiosis in another recent thread ) are consistent enough to map total length of matching chains directly to consanguinity.

Calibration of the Y-chromosome mutation rate has become rather accurate. We can now now see a rapid fan-out of the Amerindian haplogroup coinciding in time precisely with the archaeological fan-out of Amerinds; R-P312 had a spectacularly rapid fan-out coinciding in time with the rapid fan-out of the Bell Beaker culture; and so on. DNA from ancient skeletons is helping to verify and fine-tune this timing.

There is one sense in which the date of "Y-chromosomal Adam" is unclear. The split between BT (Y-ancestral to 98+% of living males) and the second largest group (A1b1, Khoisan etc.) can be dated to about 130,000 years ago, but there were much earlier split-offs of groups that are now rare. And only recently it was found that some of the Mbo men in the Cameroons have the A00 haplogroup, which may have split off 100,000 years before the 2nd-earliest known splitoff! Dating is less reliable when there is much disparity and, anyway, an even earlier A000 might turn up!

However, the dating of the Y-chromosome tree relevant to migrations outside of Africa is becoming surprisingly well calibrated.

 

[lpetrich]

DNA sequences suggest 250 people made up original Native American founding population

The researchers examined nine noncoding regions of the DNA samples collected from populations that trace the path of the migration. This included samples of individuals from China, 10 Siberian groups and from 10 Native American populations scattered across Central and South America representing several different tribal affiliations.

...
In this new study, the researchers sequenced DNA from the nine independent, noncoding regions of the genomes from indigenous peoples distributed from China to South America spanning over 15,000 years. They determined the breeding size or founding populations by isolation-with-migration computer simulation models based on 100 million generations. Each analysis revealed founding groups were between about 229 to 300 people. This led the group to estimate the parameter for the original founding population of Native Americans of about 250 people.

As to how these people spread over the Americas,

"It wasn't a matter of a group that announced, 'Let's go follow this one,'" he said. "It was a matter of population fission among hunters and gatherers. There would be about 50 people, and when the population's fertility gets higher and higher, the population splits into the next so-called 'county' and then the next. After 15,000 years, you can put them all the way down in Argentina."

That's Michael Crawford, University of Kansas professor of anthropology.

 

[bilby]

Alaska to Tierra del Fuego is 15,000km, so the rate of 'migration' is 1km (0.6 miles) per annum, or 20 yards a week.

There's no real need to explain that. It's easily explained by people wandering a little bit further afield on each hunting/gathering trip. In fact, when you consider how naturally curious humans are, expansion at 3 yards a day seems rather slow - if anything we need to explain why populating the Americas took so long. A mere thousand years is very easily enough time to travel 15,00km on foot.

 

[Politesse]

Alaska to Tierra del Fuego is 15,000km, so the rate of 'migration' is 1km (0.6 miles) per annum, or 20 yards a week.

There's no real need to explain that. It's easily explained by people wandering a little bit further afield on each hunting/gathering trip. In fact, when you consider how naturally curious humans are, expansion at 3 yards a day seems rather slow - if anything we need to explain why populating the Americas took so long. A mere thousand years is very easily enough time to travel 15,00km on foot.

There are some fairly severe geographical barriers involved.

 

[bilby]

Alaska to Tierra del Fuego is 15,000km, so the rate of 'migration' is 1km (0.6 miles) per annum, or 20 yards a week.

There's no real need to explain that. It's easily explained by people wandering a little bit further afield on each hunting/gathering trip. In fact, when you consider how naturally curious humans are, expansion at 3 yards a day seems rather slow - if anything we need to explain why populating the Americas took so long. A mere thousand years is very easily enough time to travel 15,00km on foot.

There are some fairly severe geographical barriers involved.

Ten metres per day is not exactly a blistering pace even for finding and climbing a suitable pass through (for example) the Rocky Mountains. I still think it's surprising that it took so long.

Of course the reason for that is likely that there's not much reason to move, until the local area has become to crowded, or too depleted of easy game, to remain as viable as the untouched lands to the south.

 

[rousseau]

Alaska to Tierra del Fuego is 15,000km, so the rate of 'migration' is 1km (0.6 miles) per annum, or 20 yards a week.

There's no real need to explain that. It's easily explained by people wandering a little bit further afield on each hunting/gathering trip. In fact, when you consider how naturally curious humans are, expansion at 3 yards a day seems rather slow - if anything we need to explain why populating the Americas took so long. A mere thousand years is very easily enough time to travel 15,00km on foot.

Their movement would likely have been non-linear, and it's likely that migratory patterns were tied to a) environmental cycles and b) climate niches. It wasn't their goal to populate the Americas, it was their goal to find food.

What probably caused them to actually populate the Americas was increasing population density and pressures, which forced communities to expand into new territory where new food sources were available.

At least that's what I'd guess.

 

[skepticalbip]

Alaska to Tierra del Fuego is 15,000km, so the rate of 'migration' is 1km (0.6 miles) per annum, or 20 yards a week.

There's no real need to explain that. It's easily explained by people wandering a little bit further afield on each hunting/gathering trip. In fact, when you consider how naturally curious humans are, expansion at 3 yards a day seems rather slow - if anything we need to explain why populating the Americas took so long. A mere thousand years is very easily enough time to travel 15,00km on foot.

There are some fairly severe geographical barriers involved.

There is a theory that the first migration into the Americas was by boat, following the shorelines, collecting shellfish, fishing, and killing seals, otters, etc. for food while camping on the shoreline. If this theory has any validity then there would have been no geographical barriers. Collecting food along a shoreline is certainly a much easier task than hunting big game and paddling a small skin covered boat much easier than walking while carrying belongings on your back.

 

[Politesse]

Alaska to Tierra del Fuego is 15,000km, so the rate of 'migration' is 1km (0.6 miles) per annum, or 20 yards a week.

There's no real need to explain that. It's easily explained by people wandering a little bit further afield on each hunting/gathering trip. In fact, when you consider how naturally curious humans are, expansion at 3 yards a day seems rather slow - if anything we need to explain why populating the Americas took so long. A mere thousand years is very easily enough time to travel 15,00km on foot.

There are some fairly severe geographical barriers involved.

There is a theory that the first migration into the Americas was by boat, following the shorelines, collecting shellfish, fishing, and killing seals, otters, etc. for food while camping on the shoreline. If this theory has any validity then there would have been no geographical barriers. Collecting food along a shoreline is certainly a much easier task than hunting big game and paddling a small skin covered boat much easier than walking while carrying belongings on your back.

I feel like you are imagining a bunch of explorers going on an "adventure", rather than a large extended family more or less just trying to survive on a landscape.

How keen would you be - particularly without the advantages of post 10th century BCE technology - to make the move from tundra to rainforest? Or rainforest to desert? Adapting to an environment takes time and investment, not just physical ability to move from place to place but a motivation to migrate and the demands of learning to survive once in a new location.

Many of the regions our ancestors would have had to travel though are relatively forbidding and quite lightly populated today, even with electricity and backhoes and so forth. Especially at the time, many were the kinds of places modern Europeans call "undiscovered" or "uninhabited" or "lost" in their newspapers and adventure novels. Usually home to someone, in fact, but some homes are harder won than others and may require a complex negotiation with nature if one wishes to settle over the long term.

 

[bilby]

There is a theory that the first migration into the Americas was by boat, following the shorelines, collecting shellfish, fishing, and killing seals, otters, etc. for food while camping on the shoreline. If this theory has any validity then there would have been no geographical barriers. Collecting food along a shoreline is certainly a much easier task than hunting big game and paddling a small skin covered boat much easier than walking while carrying belongings on your back.

I feel like you are imagining a bunch of explorers going on an "adventure", rather than a large extended family more or less just trying to survive on a landscape.

How keen would you be - particularly without the advantages of post 10th century BCE technology - to make the move from tundra to rainforest? Or rainforest to desert? Adapting to an environment takes time and investment, not just physical ability to move from place to place but a motivation to migrate and the demands of learning to survive once in a new location.

Many of the regions our ancestors would have had to travel though are relatively forbidding and quite lightly populated today, even with electricity and backhoes and so forth. Especially at the time, many were the kinds of places modern Europeans call "undiscovered" or "uninhabited" or "lost" in their newspapers and adventure novels. Usually home to someone, in fact, but some homes are harder won than others and may require a complex negotiation with nature if one wishes to settle over the long term.

There are no sharp dividing lines between tundra and rainforest, or rainforest and desert. Landscapes change very gradually, particularly if you only move through them at one kilometre per annum.

Sharp boundaries, for example between forests and open land, are an artefact of long human occupation, large scale agriculture, and our obsession with property and real estate ownership. They were not a feature of the pre-human Americas.

Nobody had to learn to survive in a completely novel environment; each generation lived within 50km of their birthplace, and more likely within 20km. It's an evolution, not a revolution.