Neanderthals didn’t use their thumbs like we do, new research suggests

An analysis of Neanderthal hand bones suggests that these extinct humans had thumbs better suited to power grips, as opposed to precision grips, which could mean they used their hands differently than we do.

Researchers have found important physical differences in the thumbs of Neanderthals and modern humans (homo sapiens), suggesting that the two species used their hands in different ways. The finding, as detailed in scientific reports, may speak of behavioral differences between the two species, although this can be difficult to prove.

Technically, Neanderthals were humans, but they exhibited some key traits that, if they were around today, would make them stand out in a crowd. Neanderthals were slightly shorter and thicker than early modern humans, and they had broad noses with large nostrils. They also had a weak chin and prominent brow ridges. Their hands were also bigger than ours, and as the new research shows, Neanderthal hands didn’t work exactly the same way as ours either.

“If you were to shake hands with a Neanderthal, you would notice this difference,” Ameline Bardo, a postdoctoral research associate from the School of Anthropology and Conservation at the University of Kent, explains in an email. “There would be confusion about where to place the thumb, and for a thumb fight I think you would win in terms of speed and movement.”

Good to know.

More practical, Neanderthals’ thumbs were better suited to pinch grips – like the way we hold a hammer when we take it down. Specifically, we use these power grips, as they are also called, to hold tools or other objects between our fingers and the palm, while the thumb is used to send force. Neanderthals did not have hammers with handles, but these power grips were likely useful in gripping stone tools or when gripping stones to use as a hammer.

At the same time, this may mean that precision grips – where objects are held between the tip of the finger and thumb – may have been more challenging for Neanderthals. Challenging, but not impossible. As conflicting research from 2018 shows, Neanderthals used precision grips in manual work. What the new research suggests, however, is that precision grips were not very comfortable for Neanderthals, and they may have been more prone to power grips. Unfortunately, we can’t travel back in time and see it for ourselves, so this is likely to remain a healthy debate between archaeologists and anthropologists for the foreseeable future.

That said, and as Bardo explained in her email, their “hand anatomy and archaeological record make it abundantly clear that Neanderthals were highly intelligent, advanced tool users, using many of the same tools as modern modern humans.”

Previous research in this area showed how the shapes of Neanderthal thumb bones varied in relation to those of modern humans, but these bones were studied separately. Bardo and her colleagues sought to learn how Neanderthal hand bones actually moved through time and space, which they did by mapping the joints between the bones responsible for making thumb movements in 3D.

Specifically, the researchers looked at the trapeziometacarpal complex. More specifically, they looked at the trapezium (the wrist bone at the base of the thumb) and the proximal end of the metacarpal bone (the first bone in the thumb that joins at the wrist). They analyzed how changes in the shape or position of one bone affected the shape or position of another bone.

For the analysis, the scientists studied the fossilized remains of five Neanderthals (admittedly a small sample size), which were compared with bones from five early modern humans and 50 recent modern individuals. The results indicated a “favorite position of the thumb” in Neanderthals that was distinctively different from ours.

As the new paper points out, the joint at the base of the Neanderthal thumb is flatter than ours, and with a smaller contact area. This “is better suited for an outstretched thumb placed next to the side of the hand,” said Bardo, leading to grips that were beneficial for the use of some tools, such as spears and scrapers – tools used in hunting. One downside to Neanderthal anatomy is that it limited strong precision grips, such as using a small flake to cut meat, she explained.

In modern humans, these joint surfaces tend to be more curved, which is better for gripping objects between the pads of the finger and thumb, i.e. the precision grip.

This variation between the two species is “probably the result of genetic and / or developmental differences, but may also partly reflect the different functional requirements imposed by the use of varied toolkits,” explains Bardo. “Indeed, the variation we have found in modern humans and Neanderthals may reflect several habitual activities with their hands over individuals within each species.”

Again, we can’t know for sure, and this new article is likely to spark a debate on the matter.

What we can say, however, is that Neanderthals were successful over an extended period of time, appearing some 400,000 years ago, and becoming extinct about 45,000 years ago (and for reasons we still don’t really understand). Neanderthals were also crafty: They made their own jewelry, made cave paintings, decorated themselves with feathers, and used the lissoir – a specialized bone – to work through hard animal skins.

If precision grips were difficult for Neanderthals, we certainly wouldn’t know from the cultural archaeological record they left behind.

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