Peopling Australia and the New World

World Prehistory - Class 7

The peopling of Australia and the New World

ã Copyright Bruce Owen 2000

The peopling of Australia

Pleistocene sea level was as much as 150 m lower than today

Australia joined to New Guinea: called Sahul
Islands of Southeast Asia (Thailand, Cambodia, Vietnam, Malaysia, Sumatra, Java, Borneo, Philippines) joined into one peninsula: called Sunda, with some islands close enough for plants and animals to occasionally float across to them
separated by the Sahul strait, too deep to ever be dry land, too wide for plants and animals to cross by natural means

at least 70 km of open ocean
and this was the minimum, on the best route (which you can't pick without a map, since that is much farther than you can see)
for most of the Pleistocene, the required open sea crossing would have been even wider

Results in the "Wallace line"

a sharp division in plants and animals
for example, placental mammals to northwest, marsupials to southeast
because Sahul has been isolated from the rest of the world's land for millions of years

to get to Australia, humans had to cross the Sahul strait gap in boats

probably either on a northerly or southerly route from island to island
either way, they had to be capable of open-sea travel, with no land visible on the horizon

and not just a fluke of one boat getting across, either
there must have been numerous boatloads (intentional or not) at about the same time and landing very close to each other in order to establish a viable population

hard to believe for 40,000 BP or so...
but undeniably true

unless numerous dates are wrong

Oldest archaeological site in New Guinea (then part of the Sahul landmass) is Bobongara

groundstone waisted axes below ash dated by thermoluminescence to 38,000 BP

TL dating is not always considered reliable...

waisted axes would have been hafted and used for felling trees

probably to encourage the growth of desired wild plants...?

I have not looked at the primary source, but if convincing, this is staggeringly early for this kind of technology
Fagan describes various other Melanesian island sites from 33,000 BP on

Numerous sites in Australia (also part of Sahul) with flakes, hearths, animal bone fall between 40,000 BP and 30,000 BP

many dated by radiocarbon
there are claims of much earlier sites, but all are debatable

dates of 45,000 BP, 50,000 BP, 75,000 BP, even over 100,000 BP, all by TL
recent dating of some of these using radiocarbon has produced much more recent dates, in the 22,000 to 10,000 BP range

Lake Mungo region

numerous sites, including shell middens back to 37,000 BP
i.e. early part of the Upper Paleolithic
hearths and shells radiocarbon dated to around 32,000 BP

hearths contained charcoal, fish, mammal bones, shells

tools

core and pebble tools
bone tools

burials

oldest cremation known (26,000 BP)
some with red ochre
gracile, modern-looking crania that do not resemble the more robust modern Australians

there is no particular reason to assume we have the very first occupants at Lake Mungo

the first inhabitants would have been few and scattered, and probably hard to see archaeologically
so how long before Lake Mungo were people in Australia?

all modern H.s.s.

about the same time as they appear in Europe
but 50,000+ years after they appeared in Africa!
did modern H.s.s really stay in Africa for 50,000 years, then suddenly burst out and start migrating?

the "replacement" model

do archaic H.s.s. develop into modern H.s.s. simultaneously around the world?

the "multiregional" model

is this a coincidental pattern in very incomplete data?
is this associated with whatever cultural and/or cognitive changes went along with the shift to the Upper Paleolithic?

Most of these early Australian sites were near the coast or along major rivers and lakes

fits with initial population by marine-oriented people (the kind who have ocean-going boats!)
as opposed to big game hunters or other adaptations

The peopling of the New World

* Presentation by Hans van Boldrik: "Clovis, the first Americans?"
Pleistocene sea level lower than today

uniting Siberia and Alaska with a region of land called Beringia (where the Bering Sea is today)

thought to have been a broad, flat, largely treeless plain
but largely ice-free
probably populated by large herd animals
thus attractive to tundra hunters of Asia

but beyond Beringia, the path to the rest of the New World was often blocked by glaciers that covered much of northern North America

the assumption is that people would not live and travel long distances on top of terrestrial ice sheets

so people try to reconstruct locations and dates of "ice-free corridors"
or argue for people walking or boating right along the coastline

When did Asians cross into North America?

cold periods that exposed Beringia would also have been the most severe climatic periods in northern Asia, inhibiting movement of people northwards
First known humans in northeast Asia -- the first potential immigrants to the New World -- date between 38,000 and 28,000 BP

that is, early in the Upper Paleolithic
but this early evidence is weak

a reasonable population was established by around 16,000 BP

that is, contemporary with the Magdalenian culture in Europe, the later part of the Upper Paleolithic

this was happening about the same time as modern Homo sapiens were populating Europe

the difference is that Europe already had archaic sapiens (Neanderthals) there, and had had H. erectus living there before them
northeast Asia was uninhabited by people until modern Homo sapiens arrived with Upper Paleolithic technology and cognitive abilities

Fagan focuses on D'uktai culture

central northeastern Asia
hunters who made microblades using wedge-shaped cores
could date very early, like 32,000 BP, but dating is problematic and most would put D'uktai around 16,000 to 10,000 BP
still a potential source of immigrants across Beringia

except that microblades don't appear in North America until well after the first immigrants
so they would have been either introduced by later immigrants, or locally developed

D'uktai was probably only one example of many cultures in the general region and time from that could have provided immigrants

presumably the earliest did not use microblades

Ushki sites (Kamchatka Peninsula)

stratified living surfaces buried under volcanic ash
"several large, peanut-shaped dwellings"
a burial with red ochre
hunted bison, reindeer, probably mammoth, fished salmon
lowest levels date to 14,000 BP (12,000 BC)
small, stemmed, bifacial points like some known from Alaska

these bifacial points resemble those from the earliest sites and levels in Alaska, before the microblade tradition
but they did not make fluted points, like Clovis...

indicates a potential source of immigrants by at least this time

not surprising, but reassuring to actually find them
but note that first immigration to New World could well have occurred even earlier than this

cold period called the Wisconsin glaciation from about 117,000 to 13,000 BP

North America covered by ice sheets
the glaciers advanced and retreated numerous times within the Wisconsin glaciation
in the Great Lakes area, at least, there were 5 periods of glacial advance

Beringia was probably exposed for long periods between 60,000 and 13,000 BP

so immigration was probably during that time
if humans could get to Australia across open sea by 40,000 BP, why assume that a land bridge was necessary?

why not cross the Bering strait or hop along the coastline to the New World?

but ice sheets cut off Alaska from the rest of North America

Alaska more a part of Asia than of North America
there would sometimes have been an "ice-free corridor" from Beringia to continental North America

probably between 40,000 and 21,000 BP

but for this period, there is still no convincing evidence of people being here
although there are a few debatable hints

and a brief period after 14,000 BP during which Beringia was still exposed and the ice was retreating
but probably a rough, hostile terrain that would not necessarily have been an appealing area for hunters

theories of when (and how):

Migration by land:

immigrants may have come across in those periods with both Beringia exposed and ice-free corridors present
or they could have come into Alaska first, then moved south later as the ice-free corridor opened
in either case:

the timing would be determined by the availability of a suitable inland ice-free corridor
and the people would probably have been hunters, probably focussing on large, herding animals of the tundra

Migration by coast and/or sea

immigrants may have floated across the Bering strait on sea ice even during a period when Beringia was not exposed
or they could have had good enough boats to make it across even without Beringia
or they could have walked to Alaska and then gone south along a possibly ice-free coastal strip at almost any time

on foot
or with boats, which would have allowed them to easily pass stretches where the ice reached the sea

in these models:

there are more options for the timing; the "ice-free corridors" do not limit the possible dates of initial immigration to continental North America
the people would probably have been coastal foragers/fishers/marine mammal hunters

we obviously need some more evidence to select between these models

of course, various combinations of both may have occurred...
and each route may have been used by more than one group, or during more than one period

generally agreed that the first immigration was before 12,000 BP, but how much before is debated

Very little archaeological evidence of the initial immigrants in Beringia

probably few people
Fagan describes 3 sites in Alaska with dates back to 9700 BC (11,700 BP)

these represent early, but not the first, occupants of North America
because there are earlier sites to the south in both North and South America

presumably, we have just not found the earliest Alaskan sites yet, or they have not been preserved

We know that people were in North America before 12,000 BP, and probably by 14,000 BP or earlier, from Meadowcroft Rock Shelter

in Pennsylvania

We know that people had already reached southern South America by 12,500 BP, from Monte Verde

if they had already gotten that far south, presumably people had entered North America centuries (or more) before that
more on this site later...

Biological evidence on the first immigrants

dental traits of most Native Americans outside of Alaska are similar and match a suite of traits from northern China

called the "sinodont" condition
northern China is not so close to Beringia...

two dentally different Native American groups are found in Alaska

more like other northeast Asian populations

implications

there may have been multiple "waves" of immigration from different sources
probably the first "wave" came from a sinodont population
then later "waves" from other populations were restricted to Alaska, because the good territory was already taken

genetic evidence of various types...

linguistic evidence: glottochronology

calculation of the degree of difference between languages, and the time it takes for those differences to arise
recent glottochronology studies suggest that Native American languages must have been diverging for several tens of thousands of years (estimates from 22,000 to 40,000 years...)
assuming that all this variation happened in the New World, the initial population of the New World must have been much earlier than archaeologists think
but there are big assumptions here, and many people do not put much faith in this method

looks likely that there were at least two, probably more, waves of immigration across the Bering area

first immigrants pre-13,000 BP
ancestors of modern Eskimo around 4000 BP
quite possibly others

the spread of people throughout North America

the Paleoindian period: from the first arrival of people to about 7000 BC
once thought to have started with people who made Clovis points

fluted

this style is not known from Alaska or northeast Asia
so it was probably invented in continental North America

date to a narrow range about 11,200 to 10,900 BP (in Fagan; other sources vary slightly)
populated most of North America east of the Rockies
many Clovis sites known throughout much of North America, and all the way south to the tip of Tierra del Fuego
makers of Clovis points were apparently mobile big game hunters

mostly known from bison and mammoth kill sites with Clovis points
presumably hunted smaller animals and ate lots of plant foods, too

debate about whether there were "pre-Clovis" inhabitants of the New World

now it is pretty clear that there were
as we have seen, a number of sites date to before the conventional beginning of the Clovis tradition
and lack Clovis tools
and several human skeletons have produced dates from 13,000 BP to 11,500 BP, before Clovis

so the very first inhabitants were not necessarily big game hunters, after all

but the first ones who existed in any great numbers and over vast expanses of North and South America were apparently Clovis big game hunters
so if not the first, they still may have been the first really successful people in the New World

dispersal across North and South America seems to have been rapid

based on Monte Verde and a few other sites in the 12,500 BP to 11,000 BP range
so if these are indeed the earliest sites, then the New World was populated in at most 1,500 years
but maybe we have just missed earlier sites in central and north America...

was the New World populated by big game hunters, or by coastal maritime foragers/fishers, or by people with some other adaptation?

early sites along the Peruvian coast suggest that the first people had a maritime focus

but it might be too early to assume that inland sites won't be found

what does Monte Verde indicate about the first inhabitants?

* Presentation by Toni Douglass on "Kennewick man"

9,300 BP
genetic affiliation?
modern political and ethical issues

Did people cause the post-Pleistocene megafauna extinctions?

Many large Pleistocene mammals went extinct at the end of the Pleistocene

North America

giant sloth, giant beaver, horse (reintroduced by the Spanish!), camel, mammoth, mastodon, lion, cheetah, "short-faced bear"

Europe and Asia

mammoth, woolly rhino, cave bear, lion

Two general theories (not mutually exclusive)

climate change
overhunting

Overhunting theory

New World megafauna would not recognize humans as predators

(Old World animals would have had a long time to evolve responses to them)

pro:

clear evidence that paleoindians did hunt many of these animals
spread of Clovis tradition of big-game hunting points is contemporary with the main extinctions
earlier climate changes did not kill off these animals

con:

some species went extinct before 12,000 BP, so Clovis hunters, at least, could not have been responsible
some species (giant sloth, giant beaver, many varieties of birds) went extinct at the same time without any evidence that they were hunted -- seems an unlikely coincidence
Old World species went extinct at the same time, even though human hunters had been there for tens of thousands of years

Climate change (either overall warming and drying, or increased variability, or both)

megafauna are more prone to go extinct when conditions change than smaller animals

climate changes could have shifted distributions of plant and animal foods of the megafauna
since megafauna need a lot of food, they are more at risk than smaller animals if food distributions change
and since they necessarily exist in smaller numbers and are more dispersed (because of high food requirements), even a minor drop in numbers could make finding mates much less likely
since generation lengths are long, gene flow is slower and evolution is slower, so they don't evolve quickly in response to climate (or predation) changes

con:

there had been big climate changes before without causing extinctions

maybe both combined to cause the extinctions

Monte Verde

Early sites (pre-10,000 BP) in the New World are very scarce
Monte Verde, in southern Chile, is both among the oldest and by far the best preserved
around 12,500 BP (10,500 BC)

based on many dates that agree

a wet site

covered by peat
waterlogged since shortly after abandonment
this preserves organic material amazingly well

environment at time of occupation

sandy knolls, small bogs, cool damp forest, by a small creek

Thomas Dillehay sees one main large, divided structure:

60-foot long tentlike structure
big enough for 20-30 people
logs and planks anchored by stakes
walls of hides on pole framework tied with junco reed cordage
rooms or areas marked off inside, each with a brazier
hide flecks in floor suggest hide covering (or it is from the walls?)

outside the structure

woodpile, wooden mortars with grinding stones
meat next to mastodon bones!
two large hearths

3 footprints!
artifacts

digging sticks
spears
mastodon tusk gouges
a few stone tools, not many, no points
bola stones (weights tied on cords; thrown at animals to entangle their legs)

a little away from the living area:

"wishbone-shaped" structure
floor soaked with animal fat
mastodon butchering
medicinal plants

based on use by modern Mapuche
some brought in from the coast, one from the north

subsistence

potato residues in wood mortars and indoor storage pits
mostly meat: mastodon, paleo-llama, small animals, freshwater shellfish

year-round occupation
visits to or exchange with the coast, 25 km (15 miles) away

seaweed, polishing pebbles, bitumen brought in from coast

division of labor: areas of the structure have different debris

suggests some people specialized in gathering coastal plants

conclusions:

proves that people entered the New World a bit earlier than had been formerly considered proved

12,500 - 13,000 BP
Dillehay suggests that they may have been there for a while already, since by the time people settled at Monte Verde, they had already

developed a lifestyle specific to this setting
learned about many of the local medicinal plants, which presumably takes a while

so the initial immigration from Alaska must be at least a few centuries earlier still
1,500 years earlier than the Clovis tradition
this site confirms the believability of similar dates from several North American sites

that were considered doubtful because of the scanty, ambiguous stone tools found in them

not all early occupants were mobile
not all depended mostly on hunting, but also on plants
lots of the technology was in wood, which we usually can't see...
unexpected complexity of economic and social arrangements

plus possible early levels about 30,000 BC!

this is effectively a separate site...
4 feet below later occupation, in a different area
24 broken pebbles, some flaked, some with use-wear
3 shallow depressions, lined with clay, with burned wood and seeds
dated to 33,000 BP (31,000 BC) !!
this is *not* considered definitely true yet!