Dunno. It seems that - evolutionarily speaking - running away from large pack predators was the standard response. Early people who stood and fought (for example) smilodons or short-faced bears would have been at a decided disadvantage, preserving a 'flight' response for future generations.
Boru
Boru
‘But it does me no injury for my neighbour to say there are twenty gods or no gods. It neither picks my pocket nor breaks my leg.’ - Thomas Jefferson