Scientists have found a massive cache of fossils and tools which indicate our ancestors were eating various kinds of meat at least 2 million years ago. As per usual, since they didn't find a hominid skeleton with a tool in one hand and a croc leg in the other, lying on top of the mound, they're not able to say exactly who was doing the butchering. More reasonable people will likely draw the conclusion this was Homo habilis's doing.