Two ancient hominid species with slightly different walking styles have met in East Africa.
Footprints preserved on what was once a muddy lakeshore show that two species, each built to walk in its own way, hung out there about 1.5 million years ago.
Kevin Hatala, a paleoanthropologist at Chatham University in Pittsburgh, said the newly discovered footprints at the northern Kenya site, as well as those previously unearthed at a nearby site, suggest up to 200,000 years of coexistence between ancient human species. Colleagues said that perhaps there is a glimpse of direct contact.
Footprints found along the ancient lakes of Koobi Fora, a series of deposits on the eastern edge of modern-day Lake Turkana, show two patterns of upright walking, scientists report Nov. 29 Reported in a book. science. Similar characteristics apply to footprints unearthed about 20 years ago during fieldwork led by Hatala at another Kenyan site, Illeret, which is about 1.5 million years old, the researchers said. (SN: February 26, 2009).
It belonged to prints showing signs of human-like foot anatomy and gait. homo erectusmay be a direct ancestor of homo sapienssays Hatara. H. erectuslived from about 2 million years ago to about 117,000 years ago, and ate a variety of energy-rich foods to support their large brains (SN: 12/18/19).
The impression is that there is little resemblance to modern human feet and walking patterns. Paranthropus boiseiInvestigators suspect. small head and large chin P.BoiseiDating back to 2.3 to 1.2 million years ago, they favored grasses and flowering plants called sedges.SN: May 2, 2011).
Researchers have known for nearly 50 years that East African fossils looked like this: H. erectus and P.Boisei It also occurred in nearby locations around the same time. But these fossils accumulated slowly, so researchers were unable to determine whether the two species lived in the same place at the same time.
Jeremy DeSilva, a paleoanthropologist at Dartmouth College who was not part of the Hatala research team, says the preserved footprints analyzed in the new study address that question. “We now know these two things for sure. [hominids] While sharing the same scenery, we walked in slightly different ways. ”
Dense footprints at the new Koobi Fora site. It consists of three sites. H. erectus Impressions and the 12 Impression Traces They Leave P.Boisei Once formed, the researchers say, they will be buried in lakeside sediment within a few days at most. So were the footprints of large birds and animals such as antelopes and wild horses.
“Whether or not homo and paranthropus People passing through the area at intervals of hours to a day, or seconds to a minute, would have been aware of each other’s presence on this shared landscape,” says Hatala.
If chimpanzees and gorillas can feed peacefully in the same tree, then it’s possible. H. erectus and P.Boisei Bernard Wood, a paleoanthropologist at George Washington University in Washington, D.C., said he “came across a 1.5-million-year-old 7-Eleven store” at the lake, which sold a variety of desirable foods. , Wood said he was not involved in the new study. .
Although footprint findings suggest that; H. erectus and P.Boisei Rita Sorrentino, a paleoanthropologist at the University of Bologna in Italy, said: “Whether or when they competed is potentially due to climatic and environmental pressures and cannot be determined with current evidence. ” he says.
Whatever happened on the ancient lakeshore, the Kenyan footprints support previous reports that upright posture varied among even older human species. At the Laetoli site in Tanzania, 3.6 million-year-old footprints contain human-like impressions of Lucy’s species. Australopithecus afarensis and chimpanzee-like footprints of an unidentified hominid species (SN: 11/13/24 ; SN: 12/1/21).
In the new study, researchers used digital 3D models of ancient hominid footprints and trails to show how modern humans, including Kenyan nomads who often wore few or no shoes, covered muddy soils like those along ancient lakes. I compared it with the one I made by crossing it. Muddy footprints made by chimpanzees provided a further comparison.
The arches of footprints created when humans walk through mud are very similar to those left behind by humans. H. erectus At the ancient lake, Hatara says: This finding shows that H. erectus He claims they moved their feet just like we do today.
P.Boisei The footprints show flatter arches than those of modern humans, indicating that their foot movements and perhaps foot anatomy were different from ours, Hatala said.
P.Boisei — but it’s not H. erectus They also had big toes that were more spread out than people today, but not to the extent observed in chimpanzees. P.Boisei‘s thumb may have been more mobile than others. H. erectus Or modern humans, Hatala suggests.
These foot differences are the basis for two relatively effective walks. “The orbit to which we belong is P.Boisei This reflects a fairly fast walking speed, and there is no evidence that they were unbalanced or unskilled at walking on two legs. H. erectus” says Hatala.
