An analysis of Neanderthal hand bones suggests these extinct humans possessed thumbs better suited for power grips, as opposed to precision grips, which could mean they used their hands differently than we do.
Researchers have found key physical differences in the thumbs of Neanderthals and modern humans (Homo sapiens), which suggests the two species used their hands in different ways. The finding, as described in Scientific Reports, potentially speaks to behavioral differences in the two species, though this could be tough to prove.
Technically speaking, Neanderthals were humans, but they exhibited some key characteristics that, if they were around today, would make them stand out in a crowd. Neanderthals were a bit shorter and thicker than early modern humans, and they had a wide nose with large nostrils. They also had weak chins and prominent brow ridges. Their hands were also bigger than ours, and as the new research points out, Neanderthal hands didn’t work in exactly the same ways as ours, either.
“If you were to shake a Neanderthal hand you would notice this difference,” Ameline Bardo, a postdoctoral research associate from the School of Anthropology and Conservation at the University of Kent, explained in an email. “There would be confusion over 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 practically, the thumbs of Neanderthals were better suited for squeeze grips—like the way we hold a hammer when we’re bringing it down. Specifically, we use these power grips, as they’re also called, to hold tools or other objects between our fingers and the palm, while the thumb is used to direct force. Neanderthals didn’t have hammers with handles, but these power grips were probably useful when hafting stone tools, or when gripping stones to use as hammers.
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At the same time, this possibly means that precision grips—in which objects are held between the tip of the finger and thumb—may have been more challenging for Neanderthals. Challenging, but not impossible. As contradictory research from 2018 shows, Neanderthals did apply precision grips when doing manual work. What the new research suggests, however, is that precision gripping wasn’t very comfortable for Neanderthals, and that they may have been more inclined towards power gripping. Unfortunately, we can’t travel back in time and see for ourselves, so this will likely remain a healthy debate amongst archaeologists and anthropologists for the foreseeable future.
That said, and as Bardo explained in her email, their “hand anatomy and the archaeological record makes abundantly clear that Neanderthals were very intelligent, sophisticated tool users and used many of the same tools that contemporary modern humans did.”
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 in isolation. Bardo and her colleagues sought to learn how Neanderthal hand bones actually moved through time and space, which they did by 3D mapping the joints between the bones responsible for making thumb movements.
Specifically, the researchers looked at the trapeziometacarpal complex. Even more specifically, they looked at the trapezium (the wrist bone at base of thumb) and the proximal end of the metacarpal (the first bone in the thumb that joins at the wrist). They analyzed how changes in the shape or position of one bone influenced the shape or position of another.
For the analysis, the scientists studied the fossilized remains of five Neanderthal individuals (admittedly a small sample size), which were compared to bones from five early modern humans and 50 recent modern individuals. Results pointed to a “favored thumb position” in Neanderthals that was characteristically 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 surface. This “is better suited to an extended thumb positioned alongside the side of the hand,” according to Bardo, leading to grips that were advantageous for the use of some tools, such as spears and scrapers— tools used for hunting. A disadvantage of the 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 among the two species is “likely the result of genetic and/or developmental differences, but may also reflect, in part, differing functional requirements imposed by the use of varied tool-kits,” explained Bardo. “Indeed, the variation we found among modern humans and Neanderthals may reflect different habitual activities with their hands across individuals within each species.”
Again, we can’t know for sure, and this new paper will likely rekindle a debate on the matter.
What we can say, however, is that Neanderthals were successful for an extended period of time, appearing some 400,000 years ago, and becoming extinct around 45,000 years ago (and for reasons we still don’t really understand). Neanderthals were also crafty, as they created their own jewelry, made cave paintings, decorated themselves with feathers, and used the lissoir—a specialized bone—for working through tough animal hides.
If precision grips were tough for Neanderthals, we certainly wouldn’t know it from the cultural archaeological record they left behind.
Source: gizmodo.com
