A Brief
History of
Humankind
Yuval Noah Harari
, An Animal of No Significance
Three important revolutions shaped the course of history: the Cognitive Revolution
kick-started history about 70,000 years ago. The Agricultural Revolution sped it up
about 12,000 years ago. The Scientific Revolution, which got under way only 500
years ago, may well end history and start something completely different. This book
tells the story of how these three revolutions have affected humans and their fellow
organisms.
The most important thing to know about prehistoric humans is that they were
insignificant animals with no more impact on their environment than gorillas, fireflies
or jellyfish.
Just 6 million years ago, a single female ape had two daughters. One became the
ancestor of all chimpanzees, the other is our own grandmother.
Over the generations, the people of Flores became dwarves. This unique species,
known by scientists as Homo floresiensis, reached a maximum height of only 3.5
feet and weighed no more than fifty-five pounds. They were nevertheless able to
produce stone tools, and even managed occasionally to hunt down some of the
island’s elephants – though, to be fair, the elephants were a dwarf species as well.
Today there are many species of foxes, bears and pigs. The earth of a hundred
millennia ago was walked by at least six different species of man. It’s our
current exclusivity, not that multi-species past, that is peculiar – and perhaps
incriminating.
Mammals weighing 130 pounds have an average brain size of 12 cubic inches.
The earliest men and women, 2.5 million years ago, had brains of about 36
cubic inches. Modern Sapiens sport a brain averaging 73–85 cubic inches.
Neanderthal brains were even bigger.
In Homo sapiens, the brain accounts for about 2–3 per cent of total body weight, but
it consumes 25 per cent of the body’s energy when the body is at rest.
Archaic humans paid for their large brains in two ways. Firstly, they spent more time
in search of food. Secondly, their muscles atrophied.
An upright gait required narrower hips, constricting the birth canal – and this just
when babies’ heads were getting bigger and bigger. Death in childbirth became a
major hazard for human females. Women who gave birth earlier, when the infant’s
brain and head were still relatively small and supple, fared better and lived to have
more children. Natural selection consequently favoured earlier births. And, indeed,
compared to other animals, humans are born prematurely, when many of their vital
systems are still under-developed. A colt can trot shortly after birth; a kitten leaves its
mother to forage on its own when it is just a few weeks old. Human babies are
helpless, dependent for many years on their elders for sustenance, protection and
education.