Originally (read: 3 million years ago) we supposedly were omnivorous gatherers/scavangers living in the forests. We only came out of the forrest when there was nothing to find (like small animals, insects, eggs but also fruits, nuts, roots, other eatable parts of plants) to seek for these things in the savannah/grasslands. Most probably we also found (and ate) bigger dead animals and what carnivores left over.
Later it seems, we left our secure home more often (also due to climatic changes causing the rain forest to disappear with the time) to strive through the grasslands and also developed tactics to scare even relatively big animals off their dead prey, so the quality of what we got got better. Basically we weren't hunters but thieves who stole other animals' meals. But in the end this seems to be the small but needed change in our diet (more, better meat, and thus more proteins) that caused our brain to develop and change rapidly (in evolutional terms).
The next step (also a result of the meaty diet) was that our tools and weaponry became so good that we, instead of just scaring them off, were able to hunt down other, if not all, even carnivorous animals.
Since that point we were hunters. Hunters by the means of "Four legs but not table, couch or chair? *stab*mnyumyumhumnumomnomnomnomnom*burp*!!"
As for the "relatively small canines" which were supposedly only good for "relatively small prey", we've never really used them to hunt down whatever sized animal, but used them to eat whatever sized animal. Also, it's not uncommon that teeth for instance grow back with the time when they are not necessary for a species to survive. But since we (still) have them, and it's pretty obvious what these are used for, we were "meat" eaters from the begin with (omnivorous, but still).
Ok, I did some further research and found something interesting:
It is believed that we somehow developed from the Australopithecus, whose ancestors seemed to be "fruit eaters" only. As mentioned earlier, due to climate changes it happened that the rain forest slowly disappeared and the environment changed towards being Savannah/grassland offering only harder to eat and digest nuts, roots, seeds instead of juicy fruits and leafs of the rain forest.
Current theories support the idea that there were different genetic lines of the Australopithecus. Some, like Australopithecus africanus (believed ancestors of the species homo), became omnivorous, and some became herbivorous (like Australopithecus robustus) and specialised to being able to eat hard roots and the like, which was for that climate and environment a perfect "move". However, climate changes happen to be of a somewhat static nature, and thus the very specialised herbivorous line was not able to adapt fast enough and accordingly at some point and went extinct.
What does that mean? The ancestors of our ancestors were most probably herbivores specialised to eat fruits (only). But our (direct) ancestors only had the chance to make it because they were able to eat omnivorous, and with that had the better diet compared to hard and dry plants. Is it naturally to eat meat? Yes. And without we would most probably not be here discussing this.
Last edited by Ray Jones; 10-08-2007 at 11:15 AM.