Neanderthal Thorax Shows Our Ancient Human Relatives Walked Upright and Breathed Differently to Us

neanderthal skull
Representative image of a Neanderthal skull. iStock

Scientists have reconstructed the ribcage and spine of a Neanderthal man that died around 60,000 years ago, leading them to make an unexpected discovery. Neanderthals do not appear to breathe in the same way as modern humans and their spines are far straighter than our own, indicating they had a upright posture.

The thorax is the area of the body where the rib cage and spine forms a cavity for the heart and lungs. Understanding the size and shape of the Neanderthal thorax is hugely important as it provides information on their balance and lung capacity, which in turn will give us a better idea of their physical capabilities.

Scientists have debated the size and shape of the Neanderthal thorax for 150 years—with some suggesting they were remarkably human-like, and others building a very different image of a barrel-chested, brutish figure.

In the latest study, published in Nature Communications, an international team of researchers used the skeleton of a Neanderthal man found in Israel in 1983. The skeleton was of great interest as some scientists suggested it had been deliberately buried, raising questions about Neanderthal society. It also represents one of the most complete Neanderthal thoraxes ever discovered.

The team used CT scans to create a 3D picture of the chest, combining images of the vertebrae, ribs and pelvic bones. This allowed them to build up a picture of what the Neanderthals' body would have been like. Findings showed that their chests were very different to that of modern humans.

The ribs connected to the spine in an inward direction that forced the chest cavity outward. This allowed the spine to tilt back slightly. It also meant their spines were far straighter than humans, without the lumbar curve toward the base. This discovery supports the idea that Neanderthals walked upright. "The Neandertal spine is located more inside the thorax, which provides more stability," lead author Asier Gomez-Olivencia said in a statement.

Photograph of the cast of the Kebara 2 skeleton as it was found. J. Trueba/Madrid Scientific Films

Researchers discovered that the shape of the rib cage indicates they had a larger diaphragm, so would have had a greater lung capacity than humans. They also said that their wider lower thorax and the horizontal orientation of the ribs would indicate Neanderthals relied more on the diaphragm for breathing—unlike humans who use a combination of our diaphragm and the expansion of the ribcage to breath.

Patricia Kramer, from the University of Washington, who is one of the study authors, said a greater lung capacity would have allowed more air to be moved in and out of the lungs. "That is useful in two scenarios," she told Newsweek. "When an individual is engaged in intense physical activity and when the air has a low partial pressure of oxygen (i.e., at high altitude). Neanderthals, in general, have quite strong muscular markings, indicating large powerful muscles, and robust/strong bones. We have already imagined them as having lives that required intense physical activity to do survival tasks. Greater lung volume may have been necessary to provide fuel for those muscles."

Kramer said the researchers do not know how Neanderthals' breathing would have differed from modern humans—this is something they are currently looking into. She is also now looking at what this tells us about how Neanderthals might have moved around their environments. "Mobility is a fundamental aspect of an individual's life, as anyone who has ever had an injury to their lower body or limbs knows, so I can't help but wonder what this information will allow us to learn about how they walked, how they carried their possessions and their babies, how their groups moved on foraging trips and who went along in the group, and where they might have traveled.

"It is fascinating, is it not, to think about them—so close to us in so many ways and yet so definitely not us."