Modern humans – we’re a remarkable species. Our powerful brains, along with our unique, dexterous hands have allowed us to build some of the most spectacular (and in some cases, destructive) things the world has ever seen. The thing is that modern humans only go back 200,000 years, at best – or do we? According to a group of researchers from Spain, South Africa and the U.S., a new discovery dates our so-called modern human hand to nearly 2 million years ago.
The small pinkie bone, unearthed in East Africa, has researchers rethinking their estimates for when, exactly, our earliest ancestors descended from the trees and opted for tool-making instead. At about 1.5 inches in length, the finger fragment also suggests that there were larger, previously unknown human-like species roaming the area, which encompasses modern-day Tanzania.
Our hands and evolution have an intertwined relationship. While fossilized hands can show where our ancestors were in terms of evolution, the hands were drivers of evolution themselves – as the human hand became more dexterous, we were free to use them to think and innovate, which led to larger brains. In the same vein, more evolved brains called for a more evolved human hand that was better able to execute the ideas early humans cooked up.
While our primate cousins have pretty articulate forelimbs themselves, no other mammal can match the dexterity of the human hand (you wouldn’t want a chimp performing surgery on you, for instance). The researchers say that’s for a couple of reasons: One is a longer thumb, which allows us to contact each finger individually and with a certain degree of power. The other is straighter finger bones, which allowed early humans to make and use certain tools.
The researchers say the thumb would have lengthened first, as our ancestors first walked on two legs. The fingers straightened out later, after trees were no longer our primary habitat. The researchers believe their discovery marks an important point in our evolution, where we finally gave up tree climbing and four-limb locomotion. Other archaeological evidence in the area suggests that this new species was larger for a reason – they routinely hauled the carcasses of large animals, sometimes weighing several hundred pounds.
There’s dissent among experts as to whether a whole species can be identified from a single bone, but one thing’s for certain: A combination of hominid and primate features were probably the norm at that period in time. Rather than search for one so-called “missing link,” it appears there may be several.