The ability to walk, stand and run on two legs is called bipedalism. This is a defining feature of us humans. The only question is when did our early relatives master this art? Some have thought it happened when we “crept” away from the trees and established ourselves on the ground. In this way, it would be easier for us to make good use of large, open areas. But now researchers from the United States and Great Britain have come up with a new theory. They believe that we first learned to walk on two legs while we were still living in the treetops. The new study is published in the journal Science Advances. What does the landscape have to say? Fiona Stewart is an anthropologist at University College London. She says the new results do not support the theory that we got up and walked when we “left” the trees. They must have arrived at this by studying the behavior of wild chimpanzees in Tanzania. These monkeys live in the Issa Valley. The area is a mixture of open, dry savannah landscape with few trees and a few patches of forest. Such a terrain would therefore be beneficial to study with regard to the previous theories. Do these chimpanzees spend more time on the ground than others of their kind? And could such a landscape have encouraged bipedalism in hominids? Chimpanzee is a primate species in the great ape family. It is the animal species that, together with the pygmy chimpanzee, also called the bonobo, shows the greatest resemblance to humans. Photo: Liran Samuni / AP Evolution timeline Ma = million years ago / Ka = thousand years ago before 7 Ma: Split between man and chimpanzee7 Ma: Sahelanthropus6 Ma: Orrorin5.8 Ma: Oldest Ardipithecus4.4 Ma: Youngest Ardipithecus4.2 Ma: Oldest Australopithecus2.8 Ma: The new discovery of the jawbone LD 350-1 in Ethiopia 2.6 Ma: Oldest stone tools (Oldowan culture)2.5 Ma: Oldest robust Australopithecus2.4 Ma: Previously oldest known Homo fossil1.8 Ma: First Homo erectus outside Africa1.5 Ma: Oldest hand axes1.4 Ma: Oldest campfire1.2 Ma: Homo erectus in Europe, last Australopithecus800 Ka: Homo heidelbergensis600 Ka: Split between the ancestors of Neanderthals and modern humans200 Ka: Homo sapiens100 Ka: First Homo sapiens outside Africa (Israel)40 Ka: Homo sapiens in Europe27 Ka: The Neanderthals are disappearing Source: The story of us, Torfinn Ørmen; B. Villmoare et al. Science, 2015. On two legs to find food Chimpanzees are today our closest living relatives. Understanding how their behavior varies in different habitats can help us understand the ecological factors behind bipedalism, the researchers believe. They analyzed both the movements and postures of the chimpanzees in the Issa Valley. These were then compared with previous study data of chimpanzees living in dense areas of forest. The monkeys were studied for a total of 15 months. For each observation of bipedalism, the relative position of the chimpanzee was recorded. The results showed, among other things, that despite different habitats, the Issa chimpanzees did not spend less time in the trees than other monkeys. More than 85 percent of the observed events of bipedalism took place in trees. Mainly when the chimpanzees were looking for food. Will do more research The new study thus suggests that open terrain was not a catalyst for the development of bipedalism. – The trees and the search for food were probably essential for this development, says researcher and co-author Alex Piel in a press release. Nevertheless, he believes it will require more research before it can be determined whether our own ancestors behaved in a similar way. – What made us first hang from branches, and then take a walk across the savannah, asks Piel. The Issa Valley is located in the west of Tanzania in Africa. It is located in the East African Rift Valley region.
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When did man learn to walk on two legs? It may have been while we were still living in the trees, researchers believe – news Trøndelag
