Tool-making and meat-eating began 3.5 million years ago (http://www.bbc.co.uk/news/science-environment-10938453)
QuoteResearchers have found evidence that hominins - early human ancestors - used stone tools to cleave meat from animal bones more than 3.2 million years ago.
That pushes back the earliest known tool use and meat-eating in such hominins by more than 800,000 years.
Bones found in Ethiopia show cuts from stone and indications that the bones were forcibly broken to remove marrow.
The research, in the journal Nature, challenges several notions about our ancestors' behaviour.
Previously the oldest-known use of stone tools came from the nearby Gona region of Ethiopia, dating back to about 2.5 million years ago. That suggests that it was our more direct ancestors, members of our own genus Homo, that were the first to use tools...
Another step back into the deep past of out ancestry.
This is interesting, but by no means definitive. Until we discover the tools they used or figure out some way to extrapolate more data than we currently are able to from the bones that were found, the best we can do is make an educated guess that tools might have been used based on the marks we're finding on bones from that time. This will certainly be fodder for future lively debate though, and the implications of it are exciting if the suggestion that the marks were made by tools is accurate.