Which is also the primal instinct that allows for tribalism, which is really important when the other tribe is competing for a scarce resource.
Humans are social creatures, but not social with the entire world.
Humans are social creatures, but not social with the entire world.
The modern view is that most likely hunter-gatherer societies, which didn't have fixed lands and had no general reason to be territorial, had little warfare. It is only with agricultural societies, where competition for land becomes a factor, that we start finding evidence of warfare, as far as I understand.
What's interesting it's that researchers that lived with the Yanomami and other Amazonian peoples noted that most inter tribal conflicts weren't about competition for food sources-that was rather plenty- but instead for women. In polygamous societies, high status males acquired many wives and young males frequently kidnapped neighboring tribe's women which sparked constant retaliatory raids.