[Burkeman1]

Well- early humans wouldn't hunt a grizzly bear unless real hungary - there being more docile and less agressive game far more abundant. And they would be far more calory efficient in hunting- meaning they would hunt the biggest game that would produce the biggest meat yield. Taking on a mamoth or bison with a spear would be impossible. taking it on with ten spears and torches is another matter.

[merak]

Taking on a mamoth or bison with a spear would be impossible. taking it on with ten spears and torches is another matter.

Best possible case, it's still a much harder way to earn a living than simply killing deer and normal game. Aside from everything else, a speared (ten or twenty spears) mammoth would be likely to die 20 miles from where you first speared it. How ya gonna carry it home?