A new study revealed that the mysterious footprints, originally thought to have been left by ancient bears, were in fact made millions of year ago by humans.
The fossilized impressions were found at a Tanzanian site in 1976 and show a large toe, large heel, which helped to classify them as belonging a unidentified bipedal humanoid.
It suggests that more than one such species was walking on two legs 3.7 million years ago, as separate footprints found at a nearby site in Laetoli have previously been identified as the earliest definitive evidence of bipedalism in hominins.
They are believed to belong to Researchers Australopithecus afarensis — the hominin species of the famous partial skeleton ‘Lucy’, the longest-lived and best known example of one of our early human ancestors.
Although it is not clear what kind of human made the 1976 prints, the impressions show that the person who took them was either a curious cross-stepping walker or could have been navigating dangerous terrain.
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A new study revealed that mysterious footprints, shown in photo a (and b), which had been thought to have originated from ancient bears actually belonged to early human beings many millions of year ago. The impressions were compared to another footprint made by early hominins nearby (c), bears (d), and chimpanzees(e).
The fossilised impressions, which were found at a Tanzanian site in 1976 and photographed (pictured), show a large toe with a high heel. This helped to identify the fossils as belonging to an unknown bipedal hominin.
According to researchers, the footprints had been placed so that each foot was above the body’s middleline in order for the creature to reach the ground with the other.
‘Although humans don’t typically cross-step, this motion can occur when one is trying to re-establish their balance,’ said the study’s lead author Ellison McNutt, an assistant professor at Ohio University.
‘[The]The hominin may have left footprints on an uneven area.
The first evidence of hominin bipedalism was found in 1978 by five distinct footprints at Laetoli. These were linked to Australopithecus Afarensis.
‘Lucy’, who belonged to that hominin species, was discovered in the Afar region of Ethiopia in 1974 and is thought to have been a young adult when she died 3.18 million years ago.
Researchers have previously claimed that she died after falling out of a tree, offering unusual evidence for tree dwelling in the extinct species.
However, another footprint was found in the area at Site A around the same period. This led to debate.
Many believed they were created by a bear that was walking on his hind legs. Other believe that Lucy, a different species of hominin, may have made them.
McNutt, along with her associates, excavated these unique footprints again in 2019 and compared them to impressions from bears or chimpanzees.
McNutt stated that despite the growing evidence of locomotors and species diversity in hominin fossil records over the last 30 years, McNutt felt these prints merited another look.
The footprints were measured, photographed and 3D-scanned and revealed to have a large impression for the heel and big toe — both of which fit with a hominin species.
Site A’s footprint (pictured right) can be seen alongside Site G’s (right). Site G was discovered to have the first definitive evidence for bipedalism among hominins in 1978.
The footprints were measured, photographed and 3D-scanned and revealed to have a large impression for the heel and big toe — both of which fit with a hominin species. Two footprints are shown in the image.
The video analysis (pictured below) of the wild American black bear’s behaviour revealed that it rarely uses its hind legs. The footprint of the bear is shown right
Video analysis was also done on wild American black bear behavior and revealed that it rarely walks on its hind legs.
Bears only walked two feet in less than one percent of all observations. It is unlikely that the bear made footprints at Laetoli.
Jeremy DeSilva is a senior author and associate professor at Dartmouth College in anthropology.
Pictured in an artist’s impression, Lucy (pictured above) was discovered by a team of researchers in Ethiopia’s Afar region in 1974. It is believed that Lucy was a young adult when her death 3.18 million years earlier.
“They cannot walk with a gait that is similar to the Site A footprints’ because their hip muscles and knee shapes don’t allow for that type of movement and balance.
Researchers found that bear heels taper and their feet and toes are fan-like. However, early humans’ feet were squared off with a prominent big tip.
A team of researchers analyzed footprints taken from semi-wild Chimpanzees in Uganda at Ngamba Island Chimpanzee Sanctuary and two captive juveniles at Stony Brook University. The findings revealed that the heels of chimpanzees are narrower than their forefoot. It is also a characteristic shared by bears.
The heels of the Laetoli footprints are wider than those on Site A.
Site A footprints contained impressions of both a big, large toe and a smaller second digit. Although the size differences between these digits were similar to human and chimpanzees’, they did not differ from black bears.
Researchers said that these details prove the footprints are likely to have been made by hominins walking on two feet.
However, when comparing Laetoli footprints of Site A to the inferred foot proportions and morphology as well as the likely gait, it is clear that Site A footprints stand out from Australopithecus Afarensis footprints found at Sites S and G.
Other species of the human family tree predated our genus, including representatives from the genus Australopithecus (of which Lucy was a member),
“This research has provided us with conclusive evidence that the Site A footprints show there was a different species of hominin walking on the landscape in different ways and on different feet,” DeSilva said. She focuses her study on the evolution and origins of walking.
We’ve known this evidence since at least the 1970s. We just needed to rediscover these amazing footprints, and do a deeper analysis in order to reach this point.
Researchers concluded that the findings were part of an increasing body of evidence suggesting a lesser-known diversity of hominins during this period.
Nature published the study.