Power versus finesse: Neanderthals had powerful thumbs, while humans had finer control

How we think Neanderthals might have looked like. Credit: Erich Ferdinand.

A 3D analysis of the joints between the bones responsible for the movement of the thumb belonging to Neanderthals revealed how our extinct cousin might have grabbed objects. According to the analysis, the Neanderthal thumbs were better adapted to power squeeze grips, the kind you see when holding a hammer. However, this made it more challenging to employ precision grip, which may have given humans the upper hand during times when the two species of Homo were in direct competition for resources.

Neanderthals might have been able to hold a spear better than early humans, but they were lacking in other departments

Modern archaeological findings show that Neanderthals were not brutes many imagined them to be. They fashioned necklaces and other types of jewelry, and were just as elaborate and creative with their cave paintings as humans of the time. They made flower burial offerings, which points to a complex cultural heritage, as well as mastered fiber technology and likely grasped basic mathematics judging from the patterning of the yarn and cords.

By all means, Neanderthals and humans were much more similar than they were different. In fact, they interbred numerous time, a fact atested to this day by the 2% of our DNA that is of Neanderthal origin.

But, in the end, Neanderthals went extinct roughly 40,000 years ago, while humans went on to dominate the planet’s ecosystems, spreading onto all seven continents. So while Neanderthals were also clever and resourceful, humans may have had an extra edge in other areas.

Perhaps Neanderthals were more vulnerable to diseases which humans themselves may have brought with them from Africa and the Middle East. A new study published today in the journal Scientific Reports could point to a different conclusion: Neanderthals may have been overpowered technologically not because of their inferior wit but rather because of their working hands that were less adapted to precision grips.

Researchers led by Ameline Bardo of the University of Kent in the UK mapped the joints between the bones responsible for the movement of the thumb — collectively known as the trapeziometacarpal complex  — in five Neanderthals. The 3D digital models were compared to those of measurements from the same joints belonging to five early modern humans, the earliest of which lived about 95,000 years ago in present-day Israel. The comparative analysis also involved the thumb joints of 50 recently deceased modern human adults.

In Neanderthals, the joint that connects the wrist bone at the base of the thumb with the first bone in the thumb that joins the wrist was better suited for extension along the side of the hand. This thumb posture is more adapted to ‘power squeeze’ grips, the kind we would use to hold a hammer. The power squeeze grip must have come in handy for Neanderthals when they grasped spears used for hunting.

In contrast, modern humans have thumb joints that are generally larger and more curved than those seen in our extinct cousins. This configuration is more suited for gripping objects between the pads of the finger and thumb, such as holding a pen.

Ultimately, this precision grip may have helped humans develop better technologies. However, there is no way of knowing at the moment how dexterous Neanderthals truly were. After all, there’s quite a lot of variation in the dexterity of humans, and there’s no reason to believe why Neanderthals were any different. Perhaps a larger sample size would clear things up a bit.

“Results show a distinct pattern of shape covariation in Neanderthals, consistent with more extended and adducted thumb postures that may reflect habitual use of grips commonly used for hafted tools,” the authors of the study wrote.

“These results underscore the importance of holistic joint shape analysis for understanding the functional capabilities and evolution of the modern human thumb,” they added.

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