A new method of identifying human gnaw marks on bones suggest early humans got nutrition from each other's flesh.

http://news.discovery.com/archaeology/cannibalism-early-humans-bones-101213.html

* Human gnawing and chewing marks have been identified on human and other hominid bones.
* The findings support the idea that some prehistoric humans practiced nutritional cannibalism.
* The newly identified signature for human bone chewing is also helping to determine what animals early hominids ate.