J ust 300,000 years ago – a blink in evolutionary time – at least nine species of humans wandered the planet. Today, only our own, Homo sapiens, remains. And this raises one of the biggest questions in the story of human evolution: where did everyone else go?
“It’s not a coincidence that several of them disappeared around the time that Homo sapiens started to spread out of Africa and around the rest of the world,” says Prof Chris Stringer, head of human origins at the Natural History Museum in London. “What we don’t know is if that was a direct connection.”
There are many theories around the disappearance of our human cousins, and limited evidence to decipher exactly what happened. But recent studies are providing tantalising clues.
What we do know is that from about 40,000 years ago, H sapiens was the last human standing out of a large and diverse group of bipedal hominins. Hypotheses range from benign, such as H sapiens having better infant survival rates than other hominins, or climate changes pushing other species to the brink. Others suggest a more active role, such as H sapiens hunting other humans or interbreeding with them and assimilating their genetics.