Sapiens: a brief History of Humankind

Homo sapiens
had
never gone Down Under, it would still be home to marsupial lions, diprotodons
and giant kangaroos.
The End of Sloth

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The extinction of the Australian megafauna was probably the rst signi cant
ma rk 
Homo sapiens
left on our planet. It was followed by an even larger
ecological disaster, this time in America. 
Homo sapiens
was the rst and only
human species to reach the western hemisphere landmass, arriving about 16,000
years ago, that is in or around 14,000 
BC
. The rst Americans arrived on foot,
which they could do because, at the time, sea levels were low enough that a land
bridge connected north-eastern Siberia with north-western Alaska. Not that it was
easy – the journey was an arduous one, perhaps harder than the sea passage to
Australia. To make the crossing, Sapiens rst had to learn how to withstand the
extreme Arctic conditions of northern Siberia, an area on which the sun never
shines in winter, and where temperatures can drop to minus fifty degrees Celsius.
No previous human species had managed to penetrate places like northern
Siberia. Even the cold-adapted Neanderthals restricted themselves to relatively
warmer regions further south. But 
Homo sapiens
, whose body was adapted to
living in the African savannah rather than in the lands of snow and ice, devised
ingenious solutions. When roaming bands of Sapiens foragers migrated into colder
climates, they learned to make snowshoes and e ective thermal clothing
composed of layers of furs and skins, sewn together tightly with the help of
needles. They developed new weapons and sophisticated hunting techniques that
enabled them to track and kill mammoths and the other big game of the far north.
As their thermal clothing and hunting techniques improved, Sapiens dared to
venture deeper and deeper into the frozen regions. And as they moved north, their
clothes, hunting strategies and other survival skills continued to improve.
But why did they bother? Why banish oneself to Siberia by choice? Perhaps
some bands were driven north by wars, demographic pressures or natural
disasters. Others might have been lured northwards by more positive reasons, such
as animal protein. The Arctic lands were full of large, juicy animals such as
reindeer and mammoths. Every mammoth was a source of a vast quantity of meat
(which, given the frosty temperatures, could even be frozen for later use), tasty
fat, warm fur and valuable ivory. As the ndings from Sungir testify, mammoth-
hunters did not just survive in the frozen north – they thrived. As time passed, the
bands spread far and wide, pursuing mammoths, mastodons, rhinoceroses and
reindeer. Around 14,000 
BC
, the chase took some of them from north-eastern
Siberia to Alaska. Of course, they didn’t know they were discovering a new world.
For mammoth and man alike, Alaska was a mere extension of Siberia.
At rst, glaciers blocked the way from Alaska to the rest of America, allowing
no more than perhaps a few isolated pioneers to investigate the lands further
south. However, around 12,000 
BC
global warming melted the ice and opened an
easier passage. Making use of the new corridor, people moved south en masse,
spreading over the entire continent. Though originally adapted to hunting large

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game in the Arctic, they soon adjusted to an amazing variety of climates and
ecosystems. Descendants of the Siberians settled the thick forests of the eastern
United States, the swamps of the Mississippi Delta, the deserts of Mexico and
steaming jungles of Central America. Some made their homes in the river world of
the Amazon basin, others struck roots in Andean mountain valleys or the open
pampas of Argentina. And all this happened in a mere millennium or two! By
10,000 
BC
, humans already inhabited the most southern point in America, the
island of Tierra del Fuego at the continent’s southern tip. The human blitzkrieg
across America testi es to the incomparable ingenuity and the unsurpassed
adaptability of 
Homo sapiens
. No other animal had ever moved into such a huge
variety of radically di erent habitats so quickly, everywhere using virtually the
same genes.
6
The settling of America was hardly bloodless. It left behind a long trail of
victims. American fauna 14,000 years ago was far richer than it is today. When
the rst Americans marched south from Alaska into the plains of Canada and the
western United States, they encountered mammoths and mastodons, rodents the
size of bears, herds of horses and camels, oversized lions and dozens of large
species the likes of which are completely unknown today, among them fearsome
sabre-tooth cats and giant ground sloths that weighed up to eight tons and reached
a height of six metres. South America hosted an even more exotic menagerie of
large mammals, reptiles and birds. The Americas were a great laboratory of
evolutionary experimentation, a place where animals and plants unknown in
Africa and Asia had evolved and thrived.
But no longer. Within 2,000 years of the Sapiens arrival, most of these unique
species were gone. According to current estimates, within that short interval,
North America lost thirty-four out of its forty-seven genera of large mammals.
South America lost fty out of sixty. The sabre-tooth cats, after ourishing for
more than 30 million years, disappeared, and so did the giant ground sloths, the
oversized lions, native American horses, native American camels, the giant
rodents and the mammoths. Thousands of species of smaller mammals, reptiles,
birds, and even insects and parasites also became extinct (when the mammoths
died out, all species of mammoth ticks followed them to oblivion).
For decades, palaeontologists and zooarchaeologists – people who search for
and study animal remains – have been combing the plains and mountains of the
Americas in search of the fossilised bones of ancient camels and the petri ed
faeces of giant ground sloths. When they nd what they seek, the treasures are
carefully packed up and sent to laboratories, where every bone and every
coprolite (the technical name for fossilised turds) is meticulously studied and
dated. Time and again, these analyses yield the same results: the freshest dung
balls and the most recent camel bones date to the period when humans ooded

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America, that is, between approximately 12,000 and 9000 
BC
. Only in one area
have scientists discovered younger dung balls: on several Caribbean islands, in