Despite the benefits of fire, 150 000 years ago humans were still marginal creatures. They could now scare away lions, warm themselves during cold nights, and burn down the occasional forest. Yet counting all species together, there were still no more than perhaps a million humans alive. 

Our own species, Homo sapiens, was already present on the world stage, but so far it was just minding its own business in a corner of Africa. We don’t know exactly where and when animals that can be classified as Homo sapiens first evolved from some earlier type of humans, but most scientists agree that by 150 000 years ago, East Africa was populated by Sapiens that looked just like us. If one of them today put on jeans and a t-shirt then got on the subway, no one would notice. Thanks to the blessings of fire, they had smaller teeth and jaws than their ancestors, whereas they had massive brains, equal in size to ours.

Scientists also agree that about 70 000 years ago, Sapiens from East Africa spread into the Arabian peninsula, and from there they quickly overran Europe and Asia.

Look at the map below which proposes several potential routes out of Africa and Arabia that humans could have taken. Some of these routes would have involved crossing bodies of water. 

Image from Nature.com - Routes out of Africa

Over the past 10 000 years, Homo sapiens has grown so accustomed to being the only human species that it’s hard for us to conceive of any other possibility. Our lack of brothers and sisters makes it easier to imagine that we are the top of creation, separated from the rest of the animal kingdom. When Charles Darwin indicated that Homo sapiens was just another kind of animal, people were outraged. Even today many refuse to believe it. Had the Neanderthals survived, would we still imagine ourselves to be a creature apart? Perhaps this is exactly why our ancestors wiped out the Neanderthals. They were too familiar to ignore, but too different to tolerate.

What was the Sapiens’ secret of success? How did we manage to settle so rapidly in so many distant and ecologically different habitats? How did we push all other human species into oblivion? Why couldn’t even the strong, brainy, cold-proof Neanderthals survive our onslaught? The debate continues to rage.