Early Humans

Humans hunted for meat as long as two million years ago:

Ancient humans used complex hunting techniques to ambush and kill antelopes, gazelles, wildebeest and other large animals at least two million years ago. The discovery – made by anthropologist Professor Henry Bunn of Wisconsin University – pushes back the definitive date for the beginning of systematic human hunting by hundreds of thousands of years.

Two million years ago, our human ancestors were small-brained apemen and in the past many scientists have assumed the meat they ate had been gathered from animals that had died from natural causes or had been left behind by lions, leopards and other carnivores.

But Bunn argues that our apemen ancestors, although primitive and fairly puny, were capable of ambushing herds of large animals after carefully selecting individuals for slaughter. The appearance of this skill so early in our evolutionary past has key implications for the development of human intellect.

http://www.guardian.co.uk/science/2012/sep/23/human-hunting-evolution-2million-years

Eventually, it seems humans were on the menu:

All told, the evidence from Gough’s Cave suggests to Bello that cannibalism there was both practical and ritualistic. She explained that cannibalism for survival—think Donner party—seems unlikely because the site contains a huge number of animal remains, suggesting that people were not starving. In addition, if they were eating their own kind out of sheer desperation, Bellow says, they probably would not have taken so much care in removing the brain and instead would have just smashed the skull to access the fatty organ inside. Instead, she argues that processing of the human body was a tradition—people at Gough’s ate the bodies of their fellow humans for nutrition rather than letting good meat go to waste, and then produced the skull cups for ritual. In fact, Bello suspects that, given the practical benefits, cannibalism was relatively common in the past.

http://blogs.scientificamerican.com/observations/2012/09/24/in-prehistoric-britain-cannibalism-was-practical-and-ritualistic/