When it comes to evolution, we humans often (rightly) assume ourselves to be at the pinnacle. What we cede to our ape cousins in strength, we make up for with advanced brains and dextrous hands capable of using tools, honed over millennia of evolution. However, according to research out of George Washington and Stony Brook Universities, it’s us who refuse to evolve: Our hands closely resemble those of our very earliest ancestors, while chimp hands have evolved considerably.
“Human hands have not changed that much since they diverged from chimpanzees,” said Sergio Almécija, a paleo-anthropologist and lead author of the study. “Chimpanzees have actually evolved more than humans.”
Some scientists believe that right around the point of the human-chimp split (about six million years ago), our common ancestor was more chimp-like, and humans are the ones to have radically evolved. And yet, when the research team examined fossils of early humans dating between 1.9 and 4.4 million years ago, it appears little has changed over time.
By contrast, the hands of tree-dwelling apes like chimps and orangutans have evolved significantly. As time passed, their fingers got longer and their thumbs got shorter, adapting to their environment. As a result, those primates are able to traverse the tree canopy with their arms alone, whereas a brief observation of humans playing on monkey bars shows that such movement isn’t our strong suit.
The opposable thumb, which allows us to touch each of our fingertips with considerable force, is often held up as an evolutionary marvel that helped lead humans to the top of the food chain. That’s not wrong, but the lack of opposability isn’t of great concern to chimps – they simply don’t use their hands that way. Where we rely on our legs for escape and transport, they take to the trees.
In rethinking human ascension, Almécija says that neurological growth, not hand evolution, is responsible for our advanced tool use and development. In all likelihood, the two have a complex relationship – the ability to walk upright and grasp a wide variety of food sources allowed us to develop bigger brains, while those bigger brains in turn helped us create better technology to hold in our dextrous hands.
Finally, the researchers are quick to point out that our relatively unevolved hands don’t mean humans haven’t evolved. After all, our hairless bodies, upright gait and large brains are all clear signs of human evolution.
“Evolution just means change over a long time. It doesn’t mean good or bad,” said Almécija