In a recent analysis, two scientists have reported that humans may have started walking long before the original estimated period. If this holds true, the transition from ape to the planet's dominant specie may have been drawn ages earlier than most people thought.

This comes after paleoanthropologists Brian G. Richmond of George Washington University and William L. Jungers of the State University of New York,  got their hands on four million year old fossils in Nairobi, Kenya. The fossils belonged to a specie known as Orrorin tugensis, once thought to be a mere branch of the human evolutionary tree.

Orrorin's thigh bones were examined, and later described in a journal by Richmond. He called what he observed "convincing evidence to confirm Orrorin’s bipedal adaptations".

He points to the size of the specimen’s hip joint, the shape and strength of the wide thigh bone as the most compelling indicators that Orrorin did walk upright. He says the specie still probably climbed trees and built nests with this bipedal structure.

Richmond and Jergens' findings are a big boon to early theories that Orrorin is a human ancestor and not an ape as postulated by critics. Skepticism about Orrorin's place in human lineage started eight years ago when early analysis was done by the discoverer of the fossils.

Martin Pickford and Brigitte Senut dug up Orrorin's remains in Kenya and had them stored in a bank vault. The discoverers noted that what they found at the time raised a lot of questions, making it highly doubtful that Orrorin walked on two legs. The new study, however, will be carried by the journal Science, and will attempt to prove to the scientific community that there is merit in the new look.