Add this: the concept of conservation of energy in animals (not the physics definition) explains a lot of animal behavior including primal human behaviors but mostly abandoned now since we have “unlimited” access to energy.

Birds only fly up to a branch that is just out of reach of prey. Grizzly stops attacking a human when the person plays dead. Territorial fights are rarely to the death but to the point where dominance is displayed (this includes typical tough guy pose of puffing chest up and widening upper arms).