Once again we are going ever more off-topic but since we are (kind of) still discussing re-population after some kind of global catastrophe (as in the game) perhaps we get some leeway...
Yes, i hope we get some leeway here, because inter- and inbreeding of prehistoric human species can be seen as related to Desert Stalkers setting. At least the mutants are definetly not really H. sapiens sapiens anymore, and the decayed seem to have undergone also significant changes. Not sure about the hive, they could be 'just' a kind of a cult, but i think i remember something about a telepathic link between the queen and her followers? Dunno.
Let me adress some of your remarks once again before we probably should move on and put this topic to rest.
Interestingly it seems that the total Neanderthal population at any time was way below this theoretical maximum.
The bigger the animal the fewer offspring they tend to have. Humans are pregnant for nine months and are fertile again shortly after giving birth, the gestation period for neanderthals could have been something like 10 or 12 months with a bigger gap before they could conceive again. Also for the bigger part of their existence their habitat eurasia was a much harsher environment to live in than africa. There may have been enough big game for hunting, but an ice age can put serious constraints on their ability to survive in great numbers.
You assume that females didn't hunt, and I think that recent research suggests that that was not always the case.
It is true, women went hunting. However, they usually went for small game like rabbits, lizards and birds in the closer area not more than one day away. The hunt for big and dangerous animals was usually carried out by a group of men, especially if it was a campaign over several days.
Also, you don't account for the missing males. I don't think that males would have been driven away or killed on purpose to get to a certain optimum.
I think we can blame that on testosterone, the Y-chromosome and the generally more dangerous lifestyle of prehistoric men, as hunting and warfare tends to be a life-threatening business. Even nowadays, with far better medicine and a far less dangerous life, fewer boys than girls reach adulthood. So i expect a group of early humans didn't normally need to take any action beyond that.
Actually there is ample evidence of trade during the mesolithic.
Which isn't surprising, because the mesolithic age (in europe) is already very late in human history, starting at around 9.600 BC and ending with the neolithic revolution which introduced agriculture, sedentariness and the further diversification of professions.
Let me recall the introduction of potentially tradeable goods (of course the list is not exhaustive)
ceramics: roughly 20.000 years ago
goats: domesticated roughly 13.000 years ago
agriculture: roughly 11.500 years ago in the fertile crescent area
sheeps and cattle: domesticated roughly 10.000 years ago
horses: domesticated roughly 5.500 years ago
the wheel: used as potter's wheel 7.000 years ago and 1000 years later on carriages
For the overwhelming (roughly 280.000 years) part of human history those weren't available as trade goods.
As for the xenophobia, probably, but there is also evidence of Neanderthals and other sub-species breeding with anatomically modern humans.
I already stated, there was indeed some interbreeding, and of course there may have been also friendly encounters between alien groups of humans. H. sapiens existed alongside our brethren (like the neanderthals, but also H. erectus) for twohundred-thousand years, and for the bigger part of that period we were the betas: fewer in numbers (especially in the early millenias compared to H. erectus), in a smaller area (again H. erectus, who already spread to europe and asia), and weaker (neanderthals) to boot.
There is a reason xenophobia (which isn't the same as racism) is ingrained in our genetic code, and to this day we need to make a conscious effort to overcome it. Being wary of strangers
was (and to a degree still is) an important survival strategy.
Now how does this all applies to Desert Stalkers post-apocalyptic world?
Eradicate the decayed and the hive and get friendly with the mutants and absorb their gene pool into Zeta, before it happens the other way 'round.
