that long ago, humans were prey to any number of predators and then there is disease and injury, starvation, death in childbirth, etc., etc.
I’ll grant you that for the first 2000 years of man’s existence he was so violent to each other that he eventually caused his Creator to nearly wipe him out.
But 90,000 years to figure out how to protect from predators? Nah, not buying it.