It’s lonely at the top – the last human species
I think one reason for the notion that we are so special comes from the fact that there’s only one species of humans on the planet. There is such a wide gap in intelligence, culture and technology between us humans and other intelligent animals, that we could be forgiven for believing that we are absolutely unique.
This has not always been the case, however. Just 50,000 years ago almost half a dozen species of humans (including us modern Homo sapiens) inhabited Earth. Back then, you could come across fast-running Homo erectus and hobbit-sized Homo floresiensis in Asia, Denisovans in eastern Russia and Neanderthals in Europe. Our planet was crawling with species of humans, each with their own cultures, technology and languages.
As we moved out of Africa and into the Middle East, the first ones we would have encountered would have been the Neanderthals. They were short and stocky, with pale skin, blonde or red hair (and probably freckles) – a stark contrast to our long, slender African bodies with dark skin and hair. The Neanderthals had been a highly successful species with many adaptations to the Glacial European landscape, but as our own kind expanded westward they disappeared.
Further east, in modern-day Siberia and Mongolia, we would have come across the Denisovans. Nobody knows what they were like, as all we’ve found is a finger bone and a tooth, but DNA suggest they were a sister species to the Neanderthals. It is therefore highly likely they also were pale skinned and fair-haired.
Down south, in tropical Asia, we might have encountered a real oldie: Homo erectus, the most long-lived human species of all and an offshoot of our own ancestor Homo ergaster. Whilst ergaster never left Africa, erectus did, and populated most of the Asian continent for several million years. They were tall and slender like us, used fire and tools, and lived in closely knit family groups as hunter-gatherers. They would have been awesome runners, easily as fast as a modern-day Olympic athlete.
Far east in Indonesia we might have found the hobbits: Homo floresiensis. At just 1m (3 ft 6 in) tall, they were the smallest of all humans, and probably lived as hunter-gatherers deep in the tropical rain forests.
We can only imagine what it would have been like for our ancestors to meet these ‘other’ humans. Did we see them as people? Or perhaps as trolls and goblins? Did we trade with them or did we fight them? And why are they all gone and we’re the sole survivors?
As it happens, we aren’t. Or at least not entirely. Recent studies have shown that all non-African humans have a percentage of Neanderthal-DNA in their genome. We’re literally carrying around the remnants of the Neanderthal populations in our genes. Perhaps that is where we got the genes for blonde and red hair from? And people living in Papua New Guinea can boast another set of genes: those of the Denisovans. In fact, they are the only known population that have both dark skin and fair hair.
So regardless of if we saw these other species as ‘humans’ or not, we did mate with them. And perhaps that is how they disappeared – they weren’t killed or out-competed. Instead they were simply absorbed by our growing population, and their species were assimilated. Which would make us kind of like the Borg - but a kinky and oversexed type of Borg that would do whoever they came across.