Research identifies regular climbing behavior in a human ancestor

A new review led by the University of Kent has identified proof that human ancestors as modern as two million years back could have frequently climbed trees.

Strolling on two legs has lengthy been a defining feature to differentiate modern human beings, as well as extinct species on our lineage (aka hominins), from our closest living ape relations: chimpanzees, gorillas and orangutans. This new research, primarily based on analysis of fossil leg bones, provides proof that a hominin species (considered to be either Paranthropus robustus or early Homo) frequently adopted really flexed hip joints a posture that in other non-human apes is linked with climbing trees.

These findings came from analysing and comparing the inner bone buildings of two fossil leg bones from South Africa, uncovered above sixty years back and considered to have lived among 1 and three million years back. For each fossils, the exterior condition of the bones have been really equivalent showing a much more human-like than ape-like hip joint, suggesting they have been each strolling on two legs. The researchers examined the inner bone structure because it remodels for the duration of life primarily based on how people today use their limbs. Unexpectedly, when the workforce analysed the within of the spherical head of the femur, it confirmed that they have been loading their hip joints in different techniques.

The research venture was led by Dr Leoni Georgiou, Dr Matthew Skinner and Professor Tracy Kivell at the University of Kent’s Faculty of Anthropology and Conservation, and included a substantial global workforce of biomechanical engineers and palaeontologists. These benefits demonstrate that novel information about human evolution can be concealed inside fossil bones that can change our understanding of when, where and how we turned the human beings we are currently.

Dr Georgiou reported: ‘It is really interesting to be equipped to reconstruct the true behaviour of these people today who lived millions of years back and every time we CT scan a new fossil it is a prospect to discover something new about our evolutionary historical past.’

Dr Skinner reported: ‘It has been hard to solve debates regarding the diploma to which climbing remained an critical behaviour in our earlier. Evidence has been sparse, controversial and not extensively acknowledged, and as we have shown in this review the exterior condition of bones can be misleading. Further analysis of the inner structure of other bones of the skeleton could expose interesting findings about the evolution of other vital human behaviours this sort of as stone tool making and tool use. Our research workforce is now growing our get the job done to glance at palms, toes, knees, shoulders and the spine.’

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The research paper ‘Evidence for recurring climbing in a Pleistocene hominin in South Africa’ is published in PNAS. DOI: ten.1073/pnas.1914481117

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