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I would like to know if possible, however I do not want to know how it would happen but what it would create and how stable that co-existence would be. I would like to know not how it would happen as I known but what the relation between the species. This is no longer a duplicate.


marked as duplicate by Mołot, AndreiROM, kingledion, Thucydides, Vincent Dec 5 '16 at 21:55

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  • $\begingroup$ The second part of the question is too broad. If you reduced it to just the first part of the question ('is it possible for multiple sentient species to evolve on the same planet'), then it would be excellent. $\endgroup$ – kingledion Dec 5 '16 at 17:22
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    $\begingroup$ For the first part: yes it is, for example we had Homo Neanderthal and Homo Sapiens at the same time. Given that more intelligent animals tend to be more violent and that creatures in the same ecological niche tend to compete heavily I am not certain that multiple sapient species would be able to co-exist without wiping each other out. $\endgroup$ – Bellerophon Dec 5 '16 at 17:26
  • $\begingroup$ I went ahead and answered the first question, and while I was typing many comments and answers appeared. I went ahead and ran with "intelligent as humans and capable of developing tools" rather than sentient, which I think was the spirit of the question (otherwise you get into a debate about which animals can be deemed sentient). Very broad and will likely be closed soon because of it. You're new here so take a look at the tour: worldbuilding.stackexchange.com/tour and i suggest going on the meta boards to get a handle on how to ask questions. $\endgroup$ – Erin Thursby Dec 5 '16 at 17:45
  • $\begingroup$ We can't answer this because we are not 100% what drove us to this level of intelligence. We have not observed other intelligent, sapient species evolving, or whether there are planets out there where multiple species reached such a level. In other words, it's only guesswork. $\endgroup$ – AndreiROM Dec 5 '16 at 18:06
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    $\begingroup$ Here it is: worldbuilding.stackexchange.com/questions/48214/… $\endgroup$ – Thucydides Dec 5 '16 at 20:13

I believe that this question, as asked, is too broad to answer. But I can give you a partial answer.

  • Sentient species do not simply appear on the scene. They evolve from non-sentient species.
  • On the way to sentience, they usually become the apex predator on their world. A tiger is nothing against a human with a brain.
  • If another predator is a near-peer competitor, this pre-sentient species will somehow deal with it.

Of course it remains unclear just how the meeting of homo sapiens and homo neanderthalensis really played out. The early image was "nature tooth and claw" but that might have been wrong.

  • $\begingroup$ A tiger will give a human with a brain a good run for their money...but a society of humans beats tigers at a much more reliable ratio. $\endgroup$ – SPavel Dec 5 '16 at 17:36
  • $\begingroup$ @spavel - it really depends on the circumstances. If a human with a good brain knows that there's a tiger in the area, that human can build a trap and kill the tiger without it even knowing it was being hunted. $\endgroup$ – AndreiROM Dec 5 '16 at 17:56
  • $\begingroup$ Giving the human a heads-up when his senses are far inferior isn't remotely fair. Also, a human is unlikely to produce such a trap ex nihilo - he would rely on knowledge of tiger-trap-making that was experimentally developed and shared by his people. $\endgroup$ – SPavel Dec 5 '16 at 17:57
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    $\begingroup$ @spavel - so you're going from the premise that the human being is just walking through the forest, has never seen, or heard of a tiger before, finds itself face to face with one and has to survive? Doesn't that seem silly? Yes, us humans do have some collective knowledge that we pass on. How to build a basic pit filled with spikes is part of that collective knowledge. Assuming that this human being is older than 5 minutes or so, and wasn't raised in a complete cultural vacuum, then yes, knowing that there's a tiger in the area, the human has every advantage. The tiger is screwed. $\endgroup$ – AndreiROM Dec 5 '16 at 18:03
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    $\begingroup$ Did this human biologically secrete a shovel (to dig) and a machete (to cut stakes) too? And again, you are not only assuming the human knows what tigers are, but knows that one is near and an encounter is imminent (but not so imminent that there's not enough time to dig a pit)...unless you build pits every time you go into a forest, just in case? $\endgroup$ – SPavel Dec 5 '16 at 19:41

Sentience is a kinda sticky topic, as there are a lot of skeptics, but there's a lot of evidence that a great many animals on Earth are already somewhat sentient. Humans do seem to be near the top as far as cognitive ability, but many animals have been observed performing ritual activities, using tools, recognizing themselves in mirrors, and even dreaming.

Among those we've identified as the most intelligent, there are only a small handful of highly intelligent species per ecological niche. Corvids, dolphins, octopi, elephants, and apes all occupy vastly different places in their respective ecosystems. It seems a reasonable conclusion would be to only have 1 or 2 intelligent species per ecological role, as they would likely see the others as competition and push them out.

An interesting note, as far as reactions to other sentient species go, most highly intelligent animals with evolved limbic systems (mammals mostly), tend to recognize each other's intelligence and attempt to protect them from time to time. There have been numerous stories about wild elephants protecting humans and dolphins protecting overboard humans from sharks. The nature of the interaction between intelligent species is likely to be highly varied and will depend on the specifics of the type of intelligence those creatures evolve.

  • $\begingroup$ You seem to be confusing sentience with sapience. Most living creatures are sentient to some level. Cats and dogs feel love, hate, fear, etc. It's observable, and it's nothing special. Sapience, however, is a strictly human trait on Earth. It refers to our self awareness, a trait which no other animal, to our knowledge, exhibits. On top of all that, we are also the most intelligent species on Earth by a rather wide margin. Your stories of "sentient species defending one another" are also pretty thin "evidence". Elephants have also been known to attack people, for example. $\endgroup$ – AndreiROM Dec 5 '16 at 17:55
  • $\begingroup$ Fair point. I just referenced sentience because OP's unedited request asked about sentience. $\endgroup$ – John Kossa Dec 5 '16 at 19:18

How different they could be would depend on the environment they evolved in.

Here's what you would need to achieve this.

Isolated populations that still have plenty of room to evolve. Take a good look at animals in Australia and the Galapagos Islands. There are animals there which you can't find anywhere else, but the humans, they travelled there about 50,000 years ago, likely by sea from Asia. So, what you want are lots of places that are even more isolated than that--bigger oceans that are more difficult to cross, or hazards lasting 10s of thousands of years which divide land, giving each area an opportunity to evolve intelligent life-forms.

When they do meet, they have to cooperate rather than destroy each other, and they have to be genetically distant enough not to interbreed. Neandertals ended up "disappearing" into modern humans. They were different enough to be genetically distinct, but not so different that they couldn't be absorbed into the population. And yes, many think that they were a different species of the same Genus, Homo, which had a common ancestor.

Cooperation will be more likely if they aren't competing for the same resources and if they each have something the other needs. What that could be is up to you.

How different they would be...well...it's your world and that's WIDE open.

  • $\begingroup$ I don't think that your requirements will necessarily lead to the evolution of a sapient species. Humans did not evolve in isolation, or in a "friendly", "cooperative" environment. On the contrary, they had to put their brains to good use and survive the challenges that nature, and predators threw at them. Furthermore, there's no good evidence that Neanderthals were "absorbed" into "modern humans". In fact, evidence points to them having died out, quite often by our hand. There exists evidence of interbreeding, but all signs point to it not having been viable. $\endgroup$ – AndreiROM Dec 5 '16 at 17:59
  • $\begingroup$ @AndreiROM The isolation is there so that they can evolve separately not so that they don't meet challenges. The cooperation is there so that the different species don't kill each other off when they do meet. Really depends on what you mean by good evidence. I want to avoid a modern-man vs. Neanderthal competition for resources, which is why I think they need to be different enough to cooperate rather than compete. I am using a National Geographic article that sites sources: news.nationalgeographic.com/news/2014/01/… $\endgroup$ – Erin Thursby Dec 5 '16 at 22:01
  • $\begingroup$ @AndreiROM It was mainly competition with us and the inability to adapt to changing conditions, but there's a bit of Neanderthal DNA in a lot of us. Not much, but some. When the two (or three) species meet it's important that they a) need each other and b) aren't competing for the same things. Without that, the primitive versions of these species will wipe each other out. That's what I am trying to prevent. $\endgroup$ – Erin Thursby Dec 5 '16 at 22:04

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