I'm half-remembering things from an article I probably read years ago. Upon a quick search, this looks like a decent source maybe? http://www.unm.edu/~hkaplan/

I'm half-remembering things from an article I probably read years ago. Upon a quick search, this looks like a decent source maybe? http://www.unm.edu/~hkaplan/KaplanHillLancasterHurtado_2000_LHEvolution.pdf http://www.unm.edu/~hkaplan/KaplanHillLancasterHurtado_2000_... As another poster pointed out, we can't really know how long people lived in prehistory. The numbers come from contemporary hunter-gatherers.