In the past decade, a burst of research has debunked the unflattering reputation 19th-century scientists pinned on Neanderthals.

We now know that they were creative, caring, and cognitively similar to Homo sapiens.

A study released Tuesday in Nature Communications continues the great Neanderthal debunk by nullifying yet another misconception about our ancient relatives:

Neanderthals weren’t actually a hunched-over people, like the drawings of cavemen lead you to believe.

As the video above shows, 3D virtual reconstructions reveal that Neanderthals were equipped with straighter spines than modern humans have. These models were created from CT scans of ancient bones that belong to a 60,000-year old male skeleton unearthed in a cave in northern Israel. This specimen, known as Kebara 2, is the most complete Neanderthal skeleton found to date.

Study co-author Patricia Ann Kramer, Ph.D., a professor of anthropology at the University of Washington, tells Inverse that Kebara 2’s skeleton demonstrates that while Neanderthals and humans share key attributes, our extinct relatives were still distinctly different from our species.

“The more we learn about the form of Neanderthals, the more different it appears to be in subtle ways,” Kramer says. “They are so like us culturally, and Neanderthals and modern humans interbred, but there are interesting differences in form.”

neanderthal skeleton
Comparison of Kebara 2's thorax (in blue) to a modern human sample (in grey). 

Kramer and her colleagues pinpointed these differences in form by specifically focusing on Kebara 2’s thorax — the area of the body that contains the rib cage and upper spine. They used CT scans of his vertebrae, ribs, and pelvic bones to meticulously digitally reconstructed his ribcage. The virtual reconstruction revealed that his ribs connected to the spine in an inward direction, and he lacked the lumbar curve Homo sapiens share. Instead, his chest cavity was forced outward and his spine was tilted slightly back.

Neanderthals Were Probably “Turbo-Breathers”

The shape of the rib cage suggests that Kebara 2 and other Neanderthals had a larger diaphragm than Homo sapiens — a clue that indicates they had a greater lung capacity. It’s previously been suggested that Neanderthals were capable of “turbo breathing,” meaning they could take in much more air with each breath. But that hypothesis was based off their facial morphology. Here, although the reconstruction does not show a larger skeletal thorax, rib alignment still indicates that they had a larger total lung capacity than we do, lending support to the turbo breathing hypothesis. Scientists hypothesize this ability evolved because of Neanderthals’ large energy expenditure or because they lived in high altitudes, but the exact reason isn’t clear.

“We usually think of Neanderthals as being hugely muscular, so maybe they need enhanced lung capacity to use those big bodies,” Kramer explains. “But the curve of the ribs into the spine and the shape of the ribcage in cross sections are not fully understood — yet!”

While these results add crucial pieces to the puzzle of Neanderthal existence, Kramer says that, to her, the best part of the study is the “new questions it prompts us to ask.” Before this team reconstructed the thorax, scientists didn’t even know they needed to rethink their assumptions about how Neanderthals breathed and how they moved. Her lab plans on continuing to study the mobility of Neanderthals, inspired to figure out what life was like for juvenile Neanderthals next.

Abstract:

The size and shape of the Neandertal thorax has been debated since the first discovery of Neandertal ribs more than 150 years ago, with workers proposing different interpretations ranging from a Neandertal thoracic morphology that is indistinguishable from modern humans, to one that was significantly different from them. Here, we provide a virtual 3D reconstruction of the thorax of the adult male Kebara 2 Neandertal. Our analyses reveal that the Kebara 2 thorax is significantly different but not larger from that of modern humans, wider in its lower segment, which parallels his wide bi-iliac breadth, and with a more invaginated vertebral column. Kinematic analyses show that rib cages that are wider in their lower segment produce greater overall size increments (respiratory capacity) during inspiration. We hypothesize that Neandertals may have had a subtle, but somewhat different breathing mechanism compared to modern humans.