Considering the colossal impact that Homo sapiens have made on the planet, it's mind-boggling that our species has only been around for approximately 300,000 years. But what's perhaps even more amazing is that when anatomically modern humans first emerged, they shared the planet with at least eight other human species.
You're probably familiar with Neanderthals (who continue to "live on" in our DNA), but three hundred millennia ago, the planet was populated by a wide range of additional human species, including Homo floresiensis, H. naledi, H. luzonensis, H. rhodesiensis, H. erectus, and the relatively little-known Denisovans and Red Deer Cave People.
For most of the six million years since humans split with ancient chimpanzees, numerous branches of the genus Homo coexisted. They lived in different yet often overlapping regions, and followed their own evolutionary trajectories. Of course, Homo sapiens is the only one of those species that still exists, and many anthropologists have laid the blame for the extinction of the others squarely at our feet. This is the only time in history that a single human species has existed on its own.
Humans, humans, everywhere:
- The Smithsonian National Museum of Natural History lists 21 hominin species that emerged since humans and chimpanzees last shared an ancestor. This is a conservative estimate, and there are likely to be many more, as new fossilized remains are constantly being discovered and DNA sequenced.
- The average European has approximately 2% Neanderthal DNA.
- There is evidence that Homo sapiens and Denisovans coexisted in Eurasia as recently as 15,000 years ago. Today, many people of Melanesian descent have Denisovan DNA.