Survival of the Friendliest
Even warfare is a highly collaborative activity. Everything about preparing and engaging in the most violent activity known to nature is governed by cooperation. Training, logistics, tactics, strategy, all of these things are greatly aided by working together.<p>In the wild, the <i>only</i> creatures that can hunt alone are apex predators, of which there are only a handful in any given ecosystem. Every single other species has to band together to eat and protect themselves.<p>That we ever thought anything different is just silly.