A new study reveals that the ancient humanoid ancestor Homo erectus was the first to be able to travel long distances despite having a “wide and deep chest” like Neanderthal.
Researchers at the Natural History Museum in London have examined the rib cage of the famous skeleton of Homo erectus – Turkana Boy – to better understand the breath of the species.
This is the first time that the details of the ribcage have been studied and revealed in every detail by scientists – and it’s nothing like what they expected based on his legs and arms.
Homo erectus had a sturdier build than a long distance runner̵
Fred Spoor, senior author of the Natural History Museum study, said Homo erectus would be “more rugby player than skinny athlete”.
Researchers from the Natural History Museum examined the rib cage of the famous skeleton Homo erectus Turkana Boy (right) to better understand the breathing of the species. In the photo on the left is a reconstruction of the artist from Homo erectus
Previously, experts thought that ancient hominid species had to have a much leaner body to allow them to travel long distances, but this turned out to be false.
Fred Spoor of the Natural History Museum and senior author of the study said that this has implications for our understanding of human evolution.
“It appears that the completely modern human body shape evolved more recently than previously thought, rather than two million years ago when Homo erectus first emerged,” explained Professor Spoor.
The evolution of the modern shape of the human body is important for understanding how we and our ancestors have adapted to our natural environment.
As modern humans – Homo sapiens – we have a relatively tall and slender body shape that contrasts, for example, with short, short and heavy Neanderthals.
The ribs of modern humans (left), Turkana Boy (center) and Neanderthal (right), shown in front view (top row) and left side view (bottom row) Individual fossils of Turkana Boy ribs and vertebrae (KNM -WT 15000) which were used to rebuild his rib cage using virtual computer techniques
Scientists have long speculated that the shape of our body originated with the early representatives of Homo erectus, but it may not be so.
Homo erectus first emerged in the context of climate change and elusive forests in tropical Africa over two million years ago.
Our tall and thin bodies seem evolutionarily advantageous in the expanding hot and dry savannah, helping to avoid overheating and adapting well to bipedal running over long distances in more open terrain.
The fossils attributed to Homo erectus, examined before the chest study, appeared to indicate longer legs and shorter arms than our previous ancestors, which would have been useful for running long distances.
This is in contrast to the australopites, which were bipedal when they were on the ground, but still maintained some commitments for life in the trees.
Several modern bodily features are particularly clear in the 1.5 million-year-old fossilized remains of a teenage Homo erectus found just west of Lake Turkana, Kenya.
Known as the Turkana Boy, it is the most complete skeleton of a fossil human ancestor ever found.
Studies of how this individual walked and ran were largely limited to the legs and pelvis rather than the rib cage.
However, according to the team from the London Museum of Natural History, respiratory resistance would also have been relevant.
The problem is that getting an idea of the chest and breathing movement from a “mixture of ribs and vertebra fossils” is difficult using conventional methods.
This led the team behind this new discovery to turn to technology: thanks to modern imaging and reconstruction techniques they were able to study his rib cage and how he would breathe in more detail than was previously possible.
A three-dimensional virtual ribcage of the Turkana Boy could be reconstructed and its adult form could be expected if this teenager had fully grown.
The shape of the ribcage was compared with that of modern humans and a Neanderthal and virtual animation made it possible to study the movement of the breath.
“The results are changing our understanding of Homo erectus,” says lead author Markus Bastir, adding that his chest was wider than most modern humans.
Daniel García Martínez said that the rib cage of Homo erectus looks more like that of more squat human relatives like the Neanderthals than modern humans.
Individual fossils of ribs and vertebrae of the Turkana Boy (KNM-WT 15000) which have been used to reconstruct his rib cage using virtual computer techniques
In fact, he said that species like the Neanderthals would inherit that robust chest shape from the previous Homo erectus.
“Our body shape with flat and high thorax, narrow pelvis and thoracic chest probably only appeared recently in human evolution, with our species, Homo sapiens,” says dr. Scott Williams, co-author of the study at New York University.
So rather than we inheriting tall, flat thorax, a narrower pelvis and a narrow ribcage than Homo erectus, we were the first to develop those traits.
The article specifies that these changes in our body shape may have optimized breathing abilities for long distance running and other endurance activities.
Making modern humans the first true long-distance runner.
“Homo erectus was perhaps not the lean and athletic long-distance runner we imagined,” Spoor said, adding that he had a “larger body weight estimate than previously obtained.”
“This iconic ancestor was probably a little less like us than we portrayed him,” he added.
The article is published in Nature Ecology and Evolution.
EXPLAINED: HOMO ERECTUS EVOLVED 1.9 MILLION YEARS IN AFRICA AND HAS BEEN A “GLOBAL TRAVELER”
First thought to have evolved around 1.9 million years ago in Africa, Homo erectus was the first primitive human species to become a true global traveler.
They are known to have emigrated from Africa to Eurasia, spreading to Georgia, Sri Lanka, China and Indonesia.
They ranged in size from just under a meter and a half to more than six feet.
With a smaller brain and heavier forehead than modern humans, they are thought to have been a key evolutionary step in our evolution.
Previously, Homo erectus was thought to have disappeared around 400,000 years ago.
However, this date has been drastically reduced, with more recent estimates suggesting that they only became extinct 140,000 years ago.
They are thought to have originated a number of different extinct human species including Homo Heidelbergensis and Homo antecessor.
Homo erectus is believed to have lived in hunter-gatherer societies and there is some evidence to suggest that they used fire and made basic stone tools.