Our human ancestors used stone tools almost 1 million years earlier than previously thought, according to a new study conducted by scientists at the Max Planck Institute for

Evolutionary Anthropology in Leipzig. Their results will be published Thursday in the journal Nature.

In Ethiopia's Afar region, the researchers found two bones of two different mammals dating back 3.4 million years. The rib bone and a femur bone had chips in them that could have only been made by sharp stones used to cut flesh off an animal.

Based on this evidence, scientists now believe that humans were using stone tools far earlier than the previous theory, which dated the first such use to 2.5 million years ago.

"This discovery dramatically shifts the known timeframe of a game-changing behavior for our ancestors," Zeresenay Alemseged, the lead author and a paleoanthropologist with the California Academy of Sciences in San Francisco, said in a statement.

"Tool use fundamentally altered the way our earliest ancestors interacted with nature, allowing them to eat new types of food and exploit new territories," he added. "It also led to tool making - the precursor to such advanced technologies as airplanes, MRI machines and iPhones."

Early humans also interested in eating bone marrow

Shannon McPherron, an American archeologist on the project, added the team also found evidence of early humans, or hominids, using stones in another way.

"We also found another kind of mark on these bones - percussions marks," he said in an interview with Deutsche Welle. "Those come from when these hominids would have taken a large chunk of stone and broken open the bone and they break it open to get at the marrow. The meat and marrow are high in nutritional marrow and would have been a good source of food for these early hominids."

He added that there was circumstantial evidence that this find would occur, but that there hadn't yet been any hard evidence.

"When people look at the stone tools of 2.5 million years ago they see a level of sophistication in those stone tools that suggest there might have been an earlier phase when hominids were learning how to first manufacture stone tools," McPherron said.

Calling the researchers' find an exciting event, Leslie C. Aiello, an anthropologist and the president of the Wenner-Gren Foundation in New York, said no one had expected to find evidence of tool use at such a relatively early point in time.

"This new discovery will cause us to refine our ideas about dietary and cognitive evolution in our early ancestors," she said. "It would be nice to have some stone tools from this period and more than two bones as evidence; however, this is enough to demonstrate that there is still a lot to learn about these early phases of hominin evolution."

Advent of tools crucial to human evolution

The bones were discovered hundreds of meters from the same site in Ethiopia where a decade ago the same team found the skeleton of "Selam," an Australopithecus afarensis, an extinct species that existed on the evolutionary scale between ancient monkeys and modern humans.

Anthropologists noted that the use of tools was a crucial moment for human evolution and set humans apart from the rest of the animal kingdom.

"It shows us that two aspects of our behavior, two things that anthropologists think are really important in the story of our evolution and how we are today - meat-eating and tool use - happened even deeper in our evolutionary past than we previously thought," McPherron said.

Author: Cyrus Farivar
Editor: Sean Sinico