Neanderthals may have had a greater lung capacity and a straighter spine than us, claim scientists, contradicting the popularly held notion that the ancient humans were barrel-chested, hunched-over “cavemen.”
Researchers including those from University of Washington in the US completed the first 3D virtual reconstruction of the ribcage of the most complete Neanderthal skeleton unearthed to date.
They focused on the thorax—the area of the body containing the rib cage and upper spine, which forms a cavity to house the heart and lungs.
Using CT scans of fossils from an approximately 60,000-year-old male skeleton known as Kebara 2, researchers were able to create a 3D model of the chest.
The conclusions point to what may have been an upright individual with greater lung capacity and a straighter spine than today’s modern humans.
“The shape of the thorax is key to understanding how Neanderthals moved in their environment because it informs us about their breathing and balance,” said Asier Gomez-Olivencia, from the University of the Basque Country in Spain.
How Neanderthals moved would have had a direct impact on their ability to survive on the resources available to them, said Patricia Kramer, a professor in the University of Washington.
“Neanderthals are closely related to us with complex cultural adaptations much like those of modern humans, but their physical form is different from us in important ways,” Kramer said.
“Understanding their adaptations allows us to understand our own evolutionary path better,” she said.
Neanderthals are a type of human that emerged about 400,000 years ago, living mostly from what is today Western Europe to Central Asia.
They were hunter-gatherers who, in some areas, lived in caves and who weathered several glacial periods before going extinct about 40,000 years ago.
Studies in recent years have suggested that Neanderthals and early Homo sapiens interbred, because evidence of Neanderthal DNA has turned up in many populations.
For this model of the thorax, researchers used both direct observations of the Kebara 2 skeleton, currently housed at Tel Aviv University, and medical CT scans of vertebrae, ribs and pelvic bones, along with 3D software designed for scientific use.
“This was meticulous work,” said Alon Barash, a lecturer at Bar Ilan University in Israel.
“We had to CT scan each vertebra and all of the ribs fragments individually and then reassemble them in 3D,” he said.
They then used a technique called morphometric analysis to compare the images of Neanderthal bones with medical scans of bones from present-day adult men.
“In the reconstruction process, it was necessary to virtually ‘cut’ and realign some of the parts that showed deformation, and mirror-image some of those that were not so well-preserved in order to get a complete thorax,” said Gomez-Olivencia.
The reconstruction of the thorax shows ribs that connect to the spine in an inward direction, forcing the chest cavity outward and allowing the spine to tilt slightly back, with little of the lumbar curve that is part of the modern human skeletal structure.
“The differences between a Neanderthal and modern human thorax are striking,” said Markus Bastir, senior research scientist at the National Museum of Natural History in Spain.
“The Neanderthal spine is located more inside the thorax, which provides more stability. Also, the thorax is wider in its lower part,” said Gomez-Olivencia.
This shape of the rib cage suggests a larger diaphragm and thus, greater lung capacity.