Human ancestors continued to stay in trees even as they evolved to walk on two legs: Study

The early ancestors of humans, who evolved to walk on two legs, continued to stay in trees longer than previously thought, according to a new study by scientists at the University of Birmingham in the UK. The human ancestors may have been more adept at negotiating unstable arboreal environment than previously thought, the researchers said.

Participants in the study used light fingertip touch and were successful in improving their balance by up to 30 per cent in a simulated forest canopy environment.

Researchers said the new study backs the theory that the early human ancestors continued to exploit the forest canopy for resources even as they evolved to walk on two legs.

During the study, the video footage of swaying branches were shown to the participants while attempting to balance on a branch- like bouncy springboard.

Without support, viewing the footage destabilised the participants as much wearing a blindfold.

However, when participants were allowed to use light fingertip touch on an adjacent support, their balance significantly improved and the effort required by their thigh muscles was reduced by nearly a third.

"Most modern apes are able to move around the tree canopy by hanging with their arms or gripping with long, prehensile toes," said lead researcher on the study, Susannah Thorpe from the University of Birmingham.

"It has long been thought that the relatively short fingers and toes of our human ancestors, which evolved to allow them to use tools and to walk upright, would have prevented them from foraging in the trees," said Thorpe.

"Our research shows that our early ancestors may have been able to overcome the arboreal limitations of their evolving bodies by using a 'light touch strategy' to avoid falls and reduce energy expenditure when negotiating the unstable tree-top environment," she said.

The study was published in the journal Nature Scientific Reports.

(With inputs from PTI)