There's this what-if scenario that's been kicking around in my head for quite a while now.

Basically, what if both Homo sapiens neanderthalis and Homo sapiens sapiens had survived? What if, due to geographical factors for example, the two subspecies had had been separate long enough to form two distinct species (with no interbreeding possible), and they had both evolved culturally, meeting later than they actually did?

A possible scenario that could have made this happen would have been Homo sapiens neanderthalis colonizing the Americas, for example. Or the Ural mountains being more of a barrier, and one living East and one West of them, but that's another question (potentially even for this site?).

This is similar to What factors would allow for two dominant species on a world?, but I am mainly asking for the effects it could have on society to have two intelligent races that are quite similar in appearance on one planet.

At the time of meeting, both species would have had comparable intelligence and made at least comparable cultural / technological progress. Since I am specifically asking about Homo sapiens sapiens and neanderthalis, one species prefers a colder climate, but the regions they can inhabit overlap, and with their cultural progress (clothes for Homo sapiens sapiens :-)), they can at least exist in the same regions.

(Similar questions are What would the social implications of the creation of humanoid races be?, but that's about the late introduction of a created species, and How would multi-race humanoid evolution happen, about the evolution of similar races)

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    $\begingroup$ A couple extra questions that come to mind: How does the intelligence of each species compare? How different is their biology (not just appearance)? Can they tolerate the same climates? $\endgroup$
    – Avernium
    Commented Dec 11, 2015 at 17:40
  • $\begingroup$ @Avernium thanks for the feedback. I made an edit, though nothing too substantial - there's already an answer, so that makes me hesitant $\endgroup$
    – YviDe
    Commented Dec 11, 2015 at 17:47
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    $\begingroup$ Harry Turtledove did something similar in A Different Flesh; which had the Americas populated with Homo Erectus. The book is a collection of short stories set over several hundred years from the initial English Colonization to the present; and mostly focuses on the social impacts that contact with a different form of humans had on our society. $\endgroup$ Commented Dec 11, 2015 at 21:45
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    $\begingroup$ Turtledove's stories should win the bounty. It's a must-read. $\endgroup$
    – JDługosz
    Commented Dec 18, 2015 at 0:54
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    $\begingroup$ @AndreiROM I am offering a bounty to get a few more answers, also for the less likely scenarios. Getting more answers is a perfectly valid reason to offer a bounty, which after all comes out of my own reputation. So far, all existing answers have gotten upvotes from the new views to the question. $\endgroup$
    – YviDe
    Commented Dec 21, 2015 at 20:52

5 Answers 5


This is an interesting question, and a complicated one.

Why Neanderthals Died Off

First off, let's examine some of the reasons why experts believe neanderthals died off:

This species had incredible muscle mass, and matured earlier than us. Physically, they were much stronger than to us - a neanderthal in his prime may have been able to rip an arm off of a homo sapiens and beat him to death with it.

However, their great strength was also their biggest weakness: they could not scavenge the supplies needed to keep themselves, let alone their pregnant women, and children alive.

Basically, it is believed that they starved to death - as a species. They were also competing with homo sapiens, who required less food, and were, apparently, just a little bit smarter when it came to using tools and adapting to new situations.

Meeting Each Other

Our ancestors clearly spread throughout the entire world. These tribes traveled, by foot, across continent and oceans (over ice bridges, etc.). However, with the world frozen over to a large degree, the routes they would have followed are relatively limited. These species would have met sooner rather than later.

Being tribal in nature, and basically savages, there's only two ways their encounter could go: war, or inter-breeding.

Either way, fast forward a thousand years, and you're left with pretty much a single species.

Your Specific Question

But let's say that some Neanderthals did not starve out, and met up with homo sapiens only a few thousand years later. Would they both posses similar levels of technology? It's unlikely - look at Europeans vs Native Americans. That would give one side an advantage.


If the species can't interbreed, then they are simply competitors for the same resources. Until very recently genocide was a very acceptable answer to dealing with your competition (native Americans, anyone? What about the Mayans, or the Conquistadors? When other people have stuff we want, we've killed them off mercilessly, and we're the same species).

One species would kill the other off, with my money being placed on homo sapiens - our ancestors were simply smarter.

Possible Cohabitation?

In my opinion this is highly unlikely, but here goes.

The cultural, and technological level of each race will matter immensely in this situation. The more barbaric, the less chance of them getting along.

For the two species to co-exist (which I am defining as one species not actively trying to stomp the other one out of existence) a few key conditions would have to be met:

1. Territories don't overlap

If one group is pushing into the other group's territory looking for resources then they're bound to come to blows. This has been the most basic reason human beings have killed each other ever since we first climbed out of trees.

2. Language & Culture

If both groups have advanced to the point where they have a decently developed language then they are more likely to try and communicate.

3. Development Level

If at least one group has outgrown the hunter-gatherer stage then that might work in favor of cohabitation. Evolving communities probably means that the foundation for trading has been established, not just killing strangers on sight.

4. A Common Foe

This is very likely the only true way for Neanderthals and homo sapiens to end up allied in some way. Neanderthals are stronger than homo sapiens, while homo sapiens are craftier. If they face a danger which threatens both, then they may team up, as long as communication is possible.

Imagine a group of Neanderthals meeting a raged group of battle weary HS. Instead of killing one another on sight, the HS trade some tools for food. Intrigues by these fur clad, mysterious strangers the Neanderthals don't just kill them, but offer them shelter, etc.

What you have to do is imagine a scenario where the two groups have something to offer each other, such as the brawny Neanderthals helping the clever HS hunt some dangerous creatures, or the two groups helping each other survive some cataclysm. That's what bonds two radically different communities together. In the aftermath of these two communities getting along and forming one united front others may follow in their path.

  • $\begingroup$ +1, but I'd just like to stress how much interbreeding helps promote peace. Monarchs can trade children to unite kingdoms, South America is full of the offspring of Europeans and Native Americans, and (somewhat unfortunately) most of the slaves in abolitionist novels were white, or at least had a lot of white ancestry. $\endgroup$ Commented Dec 11, 2015 at 18:16
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    $\begingroup$ It's not established whether Neanderthals were ever a distinct species to Sapiens. Neanderthal genes are present in modern human populations. It's unknown what mixture of interbreeding and conflict ended with the disappearance of distinct Neanderthal populations. Cf interbreeding that followed human introduction of US ruddy duck "species" into Europe. $\endgroup$
    – nigel222
    Commented Dec 11, 2015 at 18:47
  • $\begingroup$ @nigel222 - we may also have shared genes simply because we share a common ancestor. Neanderthals had quite different features from homo sapiens - shorter, much broader, thicker bones, smaller brain. They have found the bones of an infant that suggests it may have been a "mongrel", but overall our features do not suggest that we are the result of a Neanderthal/homo sapiens mix. $\endgroup$
    – AndreiROM
    Commented Dec 11, 2015 at 19:00
  • $\begingroup$ @AndreiROM agree you commrent but I said not known and cited Ruddy duck ( which would have assimilated European white headed duck population had further human action not prevented thIs). Ruddy duck plumage is utterly different but preferred by White headed duck females $\endgroup$
    – nigel222
    Commented Dec 11, 2015 at 19:09
  • $\begingroup$ @nigel222 - interesting, I'll look into these ducks. $\endgroup$
    – AndreiROM
    Commented Dec 11, 2015 at 19:14

It is unlikely that the two species would have had the same level of technological development at the time when they meet. From the example of documented within-human society wide-technology gaps encounters (Tasmanians vs British, for instance), we know that the depressingly standard outcome of such an encounter is genocide.

So the most likely social implication seems to be species-cide.


This isn't a totally unknown concept, and has been covered in some detail in works of fiction. This made me immediately think of Robert Sawyer's Neanderthal Parallax, for example (where the two species separately evolved in parallel universes, and then discovered each other in the modern day).

Humans have an instinctual preference for "like". Racism is very hard to eliminate - perhaps impossible to truly eliminate - for this reason. It takes almost a conscious decision to not tend to prefer those like yourself - in hiring decisions, in who you are friends with, etc. Not to say that people can't, and don't, make friends, hire, etc. those of other races or ethnicities - but the tendency is there.

There is also the common trope of the demagogue who appeals to that tribal nature. Hitler, Trump, and many others in between and before have made their popularity through naming a minority group "other" and appealing to the majority's fear of that minority.

Finally, you can think of this as a Prisoners' Dilemma; each side has a higher incentive to attack the other than to cooperate, and the only way out where both survive is if they prove their good faith to one another many times over repeated iterations. Getting to the point where that's possible is necessary before mutual survival is likely.

As such, I would imagine that when the two cultures met, there would be a great deal of difficulty regardless of era. What kind of difficulty might depend on era, but it would not be straightforward.

  • In the pre-Nationalist era (pre-1700), you might well have the least trouble. Assuming both cultures were equally technologically able and equally powerful (say, the Neanderthals occupied North America, while the Homo Sapiens occupied Eurasia/Africa), you might end up with something not all that different than post-1700 politics. The nations would probably not get along at points, but a combination of Realpolitik and simply geographic separation would likely lead to a situation where they traded, occasionally fought, but otherwise stayed away from each other.

    If both nations stayed balanced through the Nationalist period, and made it to the Modern period, you might have a world like you have now - except with two species - similar to how different races more-or-less coexist now in most countries. If you think of this in Prisoners' Dilemma terms, you have a fairly long time when the two species can't really wipe each other out whereupon they can prove their good faith to each other; if that occurs, they may survive the technological era where it becomes possible to wipe each other out.

  • In the Nationalist era (roughly 1700-1945), if the two cultures discovered each other at that point, I think it's highly difficult to imagine one species not eliminating the other. During this time, most of our wars arose from ethnic nationalism (or, leaders' appeal to it); people began to identify much more strongly with their nation (rather than their locality), and I suspect this would have been more difficult in the case of two species. World Wars were possible at this time; not just because of weapons technology, but because it was possible to mobilize an entire nation-state into war, whereas that was not really possible beforehand. I suspect it would be challenging for each group to prove their good faith to each other before a nationalist/speciesist leader was able to mobilize their species to wipe out the other.
  • In the Global era (1946-present), I think you would have major problems still - but less likely a world war, if contact was made slowly, in stages, where each species could demonstrate its willingness for cooperation to solve the Prisoners' Dilemma. If the leaders of each side had that opportunity before it became globally known that there was another species, it's entirely possible that the two races could survive. (In Hominids etc., the difficulty of cross-universe combat made this less of an issue of course; if I recall correctly, though it's been quite a few years since I read it, there was still a significant speciesist component to our response despite the difficulty of crossing universes.) Particularly, if a few scientists got to know each other first, and then brought a few world leaders in, and then went public, I think it's possible both sides could get to an arrangement where they could both survive - but it would probably be tense for centuries.

Another possibility of course is if the two groups occupied different spaces - examples in fiction include a species occupying the oceans (think Blue Hades from the Laundry Files series), species occupying neighboring planets post-easier space travel, etc. Then, you still have the prisoners dilemma situation, but it's somewhat easier to survive because the benefits of attacking are less (as there are less common resources to fight over, when you don't occupy the same space).

  • $\begingroup$ I seriously wish I could upvote this more times because it's a great late addition and I think you would have gotten more upvotes if it hadn't been the latest answer. Nice! $\endgroup$
    – YviDe
    Commented Dec 24, 2015 at 21:40

One possible scenario I am contemplating is an initial stage of war, which seems natural to me, as we have seen it in history quite often (the Americas, for example). But if both species cover large territories, and are at a similar technological level, this might result in a stalemate situation, where over time the losses just get too big to sustain a war. There have been countries who were at war for a long time and in the end no country was a clear winner - territory may be lost or won, but the other country might not end up conquered or completely defeated. The regions far removed from the border of the species might stop sending people off to die because they are sick of losing them to an endless war fought far away from them, for example.

So in the end, total annihilation might just not be feasible in the absence of weapons of mass destruction. This could lead to trade relations between the two species, even. I wouldn't expect a deep friendship to form, and I would expect a lot of hatred and racism (can it even be called that, then?), but a sort of acceptance.

Religion would be different. With such an obvious example of another intelligent species, religions would spring up that said "our species is God's chosen one" and I can imagine others would appear that revere a sort of "dualist" system. That say that in the two species, God is showing his/her dual nature.

I have contemplated the idea that racism within a species might actually be lower in such a setting. If there is another group around that's very different from you, maybe the focus on the differences between members of one species gets weaker. On the other hand, prejudice would be expressed as groups being closer to the "rival species". Terms of hatred would be derived from whatever most visibly separates the species. Slavery would be more common in regards to the other species, maybe leading to slavery within a species not happening.

If progress picked up in one species and not the other, a society where both survive, but one is only used as slaves is possible.

If scientific progress continued the way it did, it's really a question of what comes first - a greater understanding of science bringing more tolerance, or better warfare resulting in weapons of mass destruction.

So, in essence, what I am thinking is that if the two species didn't have the means to annihilate the other, there would be phase of hatred, maybe a phase of neutrality and even trade and then either mass annihilation or actual mixing with the potential for a lot of conflict.

  • $\begingroup$ See this question for some thoughts on racism in a world of multiple species. I admit I don't really like the answer I gave, but overall I think it's an interesting question with some good answers. $\endgroup$ Commented Dec 11, 2015 at 18:24
  • $\begingroup$ @DaaaahWhoosh oh, that's an interesting question, yes. Thanks! $\endgroup$
    – YviDe
    Commented Dec 11, 2015 at 18:26

Sooner or later, one would destroy the other. We destroy cultures even very similar to ours so... something entirely different? - of course it has to give way!

But that already happened! So, I guess you want to exclude this scenario. Maybe your question is: "What would the two societies look like, if HSS and HSN didn't eliminate each other before the age of Political Correctness [my term] came?"

Well... Excuse my lame pre-historical geography skills (just imagine a more correct landscape in the cases which I am wrong) but let's say enough HSN lived in the small bottleneck between Africa and Asia. I think this is the likeliest scenario that would allow the HSN to survive the HSS expansion. They NEED the land for resources for their much more demanding bodies.

So, they coordinated a blockade somewhere in what we call modern Egypt and kept the HSN at bay.

Actually, Africa is not a bad place to be. The HSS would have used the vast resources to build a Europe-like continent in Africa. Europe would be another dreary part of Asia.

That would all seem plausible all the way in history before guns leveled the playing field. All the sword-fighting stuff the HSN could handle, using their superior bodies and some tactics.

Then, a WWI-style invasion would have gained a lot of land for the HSS but maybe not the whole of EuroAsia?

You'd have pockets of HSN in the outskirts of EuroAsia. The Americas would look the same. Let's say whichever of the America's the HSS landed in, the other one remains HSN, due to a bottleneck in the Panama area but, still, with the advent of firearms, HSN would have been pushed to the "still acceptable" north parts of North America (or south parts of South America).

Can I say the technological/social differences between the HSS and HSN are comparable to the tech/soc differences we currently have between "the west" and "the 3'rd world"? In that case, imagine something similar to what we have now: Vast amount of people still live without running water, electricity or education but as long as they play their role (=let us use their resources without uprising), we will be "politically correct" and totally ignore their problems. We would

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    $\begingroup$ Interesting answer! Is there a part missing at the end, or is that just some accidental fragment? $\endgroup$
    – YviDe
    Commented Dec 11, 2015 at 19:23

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