The untold story of our remarkable hands and how they made us human

New Scientist · Feb 17, 2026 · Collected from RSS

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Tim Booth Photography Playing a complex guitar solo ought to be impossible. To elicit the desired torrent of notes, the fingers of one hand must move nimbly around the fretboard, while the other hand plucks the strings, in a dexterous combination of speed and strength. Anyone who has watched an expert player and then picked up a guitar for themselves will understand the degree of skill required. What’s less obvious is that our hands have been shaped by evolution for tasks just like this. It might not feel like it the first time you try out this instrument, but hands with that special combination of precision and strength are a defining trait of our species. In fact, the evolution of the human hand is one of the most important stories in our origin, at least as central as that of our oversized brain. Yet for many decades, the evolution of the hand has been impossible to grasp: there were too few fossil hands and the story they told didn’t make much sense. Now, thanks to a string of new discoveries, it is finally possible to sketch out the story of how our incredible dexterity came to be – and its unexpected links with the evolution of our brain and language. How our hands are different Compared with those of our closest living relatives, chimpanzees and bonobos, our hands are highly unusual. “The human hand proportions are really different,” says Carrie Mongle, who studies human evolution at Stony Brook University in New York state. “We have a really long and a really robust thumb, compared to our fingers.” Chimps and bonobos have the opposite: long fingers and skinny, short thumbs. This is reflected in the skeleton. “The finger bones themselves in humans are relatively short and they’re straight,” says Mongle. “In a chimpanzee, they are much more curved and much longer.” These differences make it easier for us to hold objects between finger and thumb – something chimps struggle to do. That precision grip is key to everything from using tools to playing the guitar. The human thumb is also highly mobile. “Our thumbs can move in basically any direction,” says Mongle. Even the soft tissues are different. Fossils provide less information about this because soft tissues are only rarely preserved, but there are clues on the bones, like marks where muscles were once attached. Humans have very large hand muscles, says Cody Prang, a paleoanthropologist at Washington University in St. Louis, Missouri. “That’s an important part of producing the forceful precision grips.” This is further supported by a muscle called the flexor pollicis longus, which has an insertion point on the bone that forms the tip of the thumb – unlike in chimps, where it doesn’t extend so far. This muscle “flexes the thumb independently of the other digits”, says Prang. Clearly, the human hand has a lot going on. But how and why did these features evolve? An early suggestion was put forward by Charles Darwin. In The Descent of Man, published in 1871, he suggested that our dexterous hands could only evolve after we started to walk upright on two legs: “Man could not have attained his present dominant position in the world without the use of his hands… But the hands and arms could hardly have become perfect enough to have manufactured weapons, or to have hurled stones and spears with a true aim, as long as they were habitually used for locomotion and for supporting the whole weight of the body, or as long as they were especially well adapted, as previously remarked, for climbing trees.” It was a neat idea, but for decades there was no way to test it. “For a long time, there were no fossils,” says Prang. Only a handful of hominin remains were found in the 1800s. Compared with the hands of many ancient hominins, chimpanzees and gorillas, our hands have relatively long thumbs that enable a precise gripCourtesy Brian G. Richmond, et al. What did turn up in East Africa in the early 20th century, however, were stone tools made by early hominins in the distant past. Some of the most primitive – crude chunks and flakes made from banging one stone against another – were found in Oldupai (or Olduvai) gorge in Tanzania by teams led by renowned palaeoanthropologists Louis and Mary Leakey. These became known as Oldowan tools. The discoveries prompted the Leakeys to keep exploring the region, in the hope of finding the tool-makers. In the early 1960s, the Leakeys’ team discovered a partial skull accompanied by hand and foot bones. In 1964, Louis Leakey and his colleagues announced that it belonged to a new species: Homo habilis, an early member of the Homo genus to which we belong. These hominins, they said, were probably the makers of the Oldowan tools. “That would be really the first time the hand played a really important role in our understanding of human evolution,” says Tracy Kivell at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany. Which is odd, she says, because it doesn’t look particularly human-like. “The hand bones actually are really quite robust and the finger bones are still curved,” she says. “There’s nothing about it that really screams out, ‘This is a really dexterous hand’. It looks a lot more ape-like.” Even today, some researchers aren’t convinced the hand bones came from a Homo individual at all. Discovery Tours: Archaeology and palaeontology New Scientist regularly reports on the many amazing sites worldwide, that have changed the way we think about the dawn of species and civilisations. Why not visit them yourself? Lucy and other incredible fossils Many amazing fossils were discovered over the next half-century. They included Lucy, a partial skeleton of an earlier hominin called Australopithecus afarensis, from about 3.2 million years ago. There were also several examples of Paranthropus: flat-faced hominins with big teeth that seemingly lived alongside early Homo between about 2.8 million and 1.4 million years ago. But hand bones remained few and far between. “Lucy only has two hand bones,” says Kivell, a finger bone and part of the wrist. In 2003, researchers assembled a “composite” hand for A. afarensis by combining fossils from a collection found at Hadar in Ethiopia. This indicated that they had fairly human-like hands, with long thumbs and short fingers. However, the fact the hand had been cobbled together in this way meant it was open to reinterpretation, and others duly argued that A. afarensis were “intermediate between gorillas and humans” and “could not produce precision grips with the same efficiency as modern humans”. In line with this, there was no evidence of stone tools at this early period. This no-hands problem became more acute in the early 21st century, because the hominin fossil record was extended much further back. Sahelanthropus tchadensis may be 7 million years old and Orrorin tugenensis is about 6 million years old. Combined with genetic data indicating that our most recent shared ancestor with chimpanzees lived around the same time, it became clear that the story of human evolution probably spanned 7 million years – and there were still hardly any hand fossils. Then, in 2009, a spectacular hominin fossil was described, upending all our assumptions. Meet “Ardi”, or Ardipithecus ramidus, which lived 4.4 million years ago. Its discovery transformed our understanding of human evolutionJOHN BAVARO FINE ART/SCIENCE PHOTO LIBRARY In the early 1990s, palaeoanthropologists including Tim White at the University of California, Berkeley, discovered a partial hominin skeleton in the Afar region of Ethiopia. The remains were 4.4 million years old and took over a decade to analyse. They represented a new species, dubbed Ardipithecus ramidus, which the team finally described in a special issue of Science in 2009. The skeleton of “Ardi” was startlingly complete, including much of the skull, pelvis, limbs, feet and hands. The researchers argued that A. ramidus walked upright. Despite living in a wooded environment, they weren’t adapted for “suspensory” behaviours like dangling from tree branches, as chimps and other great apes are. In particular, the team said, their hands didn’t resemble those of any living great ape. “ “Our “ This had profound implications. Because chimps are our closest living relatives, it had been tempting to assume that the ancestor we shared with them was chimp-like. But Ardipithecus suggested that it wasn’t: it was an ape, of course, but not like a chimp. In which case, the last common ancestor might have had fairly human-like hands, and it was the chimps whose hands changed. This made a complete mess of everything. Why had our long-lost ape ancestor evolved hands like ours, millions of years before anyone was making stone tools? To compound the problem, Sahelanthropus and Orrorin both had traits that suggest they walked upright – again, millions of years before the oldest evidence of stone tools. This ran counter to Darwin’s original idea, that bipedalism is what freed our hands to become more dexterous. We needed more hands, and they came along soon enough – but they didn’t make the picture any clearer. The remains of Australopithecus sediba were discovered in 2008 in a cave in South Africa. They are about 2 million years old and seem to have been bipedal, but they also had a strange mosaic of Australopithecus and Homo traits. The remains included a near-complete wrist and hand from an adult female, which Kivell helped to analyse. A. sediba had the long thumb and short fingers of a Homo, but also had ape-like traits suited to tree-climbing. A similar story played out five years later, with the discovery of Homo naledi in another South African cave. This species was much more recent, around 300,000 years old, and assigned to our genus, but H. naledi still had a weird mix of Australopithecus and Homo traits. Its thumb was long and large like a human’s and its wrist was human-like, but its finger bones were long and curved like those of a tree-climbing ape. “I would put Lucy and [Au