The consensus is that humans evolved from a common ancestor as the Apes. But Apes are vegetarians and non-predatory. They are not violent. Humans are carnivores and apex predators....most aggressive species on earth. Our whole history is driven by aggression. And Homo Erectus killed so much megafauna (big game) that it put other carnivores out of business (extinction). On the surface humans look like apes but apes pig out on vegetables and cellulose all day. They have these big giant guts for fermentation of fiber. But under the surface, the human PH balance, colon size, small intestine size, method of fat storage for energy, tapered-waist and numerous other features are exactly on par with obligate carnivores. In the days of Homo Erectus, our hunting method (persistent locomotion) was by far the most ruthless hunting method there was. Our entire bodies are designed for long-distance tracking (hence the loss of fur) and throwing weapons. The common objection is that we don't look anything like lions. The response, we don't need to because the human brain was evolution's greatest innovation in terms of creating the most lethal hunter known to man. It spared the need for claws and teeth.