Our ancestors may have evolved to walk upright in trees rather than on the ground, new study suggests - CNN

CNN  — 

Humans’ quality to walk upright connected 2 legs whitethorn person evolved successful trees, alternatively than connected the ground, according to scientists studying chaotic chimpanzees successful Tanzania.

This contradicts the wide accepted mentation that prehistoric quality relatives evolved to locomotion connected 2 legs due to the fact that they lived successful an unfastened savanna environment, according to a survey published Wednesday successful the diary Science Advances.

Researchers from University College London (UCL) spent 15 months looked astatine the behaviour of 13 chaotic big chimpanzees successful the Issa Valley successful occidental Tanzania, which is location to a substance of adust unfastened onshore and areas of dense forest. Known arsenic “savanna-mosaic,” this benignant of situation is akin to that successful which our earliest quality ancestors lived.

The squad recorded each clip that the chimpanzees were upright, and whether it occurred portion they were connected the crushed oregon successful the trees.

They past compared this with instances of lasting connected 2 legs by chimpanzees that unrecorded successful densely forested areas successful different parts of Africa, and recovered that the Issa Valley chimpanzees spent conscionable arsenic overmuch clip successful the trees arsenic their forest-dwelling cousins.

This means they were not much land-based, arsenic existing theories suggest they ought to be, fixed the much unfastened situation successful which they live. In addition, much than 85% of the times that the chimpanzees walked upright occurred successful the trees, alternatively than connected the ground.

Study coauthor Alex Piel, an subordinate prof of anthropology astatine UCL, told CNN that wide held theories travel a definite logic.

“A long-held presumption has been: Less trees means much clip connected the ground, much clip connected the crushed means much clip upright,” Piel said.

However, his team’s information does not carnivore that out, alternatively suggesting that much unfastened environments were not a catalyst successful encouraging bipedalism, said Piel. “It’s not this bully logical story,” helium said.

The adjacent question for researchers is wherefore the Issa Valley chimpanzees walk much clip successful trees contempt being astir less trees than different chimpanzee communities, Piel said.

One mentation could beryllium the information that food-producing trees promote them to walk clip determination to eat, helium said, portion determination could besides beryllium a seasonal component.

In the rainy season, writer successful the Issa Valley grows to astir 6.5 feet successful height, said Piel, which means the chimpanzees are much susceptible to ambush predators specified arsenic leopards if they walk clip connected the ground.

“It could beryllium that determination is simply a melodramatic seasonal signature to this,” helium said.

Early quality ancestors would besides person faced predation successful a akin environment, according to Piel.

“It’s a truly analogous system,” helium said.

However, Piel underlined that the survey is not drafting a nonstop examination betwixt the chimpanzees and our aboriginal quality ancestors, but is alternatively providing theories that request to beryllium tested against the fossil grounds to spot what it tells america astir the anatomy of aboriginal hominids.