Could two sentient species of the same ancestor evolve to live side by side

Question

I know that two sentient species can evolve from the same origin. We can look back and see Humans, Neanderthals, and others living at the same time. But Humanity either beat the others or interbreed with them and came out on top.

I would like to know if two creatures of similar intelligence and make could live together, whether it be with one as servants or just members of society.

• The first creature is bigger than the other. They are very tall, ranging from 2.5 (8.2ft) to 3.5 (11.5ft) meters in height. They range in weight from 400 to 550 pounds (this may be too much).
• The other creature is your standard human. Average height of 5.4 feet and weight of 140 pounds.

I have thought about the square-cube law when figuring out their sizes. The atmosphere is 27.7% Oxygen, which is well above what is needed for large creatures.

I have not gotten far on the creature's psychology. Seeing that both are meant to be the humans of the story, I would say they are similar to us.

Answer 1

It will depends on your creatures physiology and behavior, but nature is plenty of symbiosis examples so let's speculate how to make this cohabitation plausible.

Despite their destructive tendencies, humans live side by side with many different mammalian species - cattle, cats, dogs, horses,... And it happens that we all have the same common ancestors - ancient mammals. But I'll take the guess that you are suggesting a much closer ancestor, eg as close at the one humans share with the other apes.

Something that is apparent in the domestication process, is that it is in the benefit of the dominant species - humans. We use dogs for guarding, cats to chase pests, horse to carry loads and move faster, cattle for food. There are some examples we domesticated monkeys to grab fruits, and nowadays monkeys are still used in medical research as a close example of human physiology.

Here, both of you species are dominant so each needs to get a benefit from the proximity of the other. You said that one is much bigger than the first one, which is an obvious advantages for bulk force works. The small species, in contrary, could be better suited for precision handicraft (eg as weavers, jewellers or blacksmiths). It also likely that your small species would be more numerous than the big one due to much lower food needs, thus for similar resources they would provide more brains and more hands.

In addition to make sure that each species would get an advantage from the other, you may want to reduce competion between these. For example, having your big species an herbivore and the small one an obligatory carnivore would prevent them to compete for the same foods. However, if they develop agriculture, fields for the cattle used by the small species would compete with the pasturages/forests required by the big species.

In our world, Sapiens humans interbred with other hominins so our current species share a few % of DNA with Neanderthals, Denisovans, and possibly others to be identified. In your setting, natural interbreeding would be impossible for obvious reasons - but maybe they could experiment with artificial insemination to create hybrids.

Having a close ancestor raise the question of the huge size difference between your species. Fortunately, we have real-life examples of species exhibiting unusual sizes when isolated on an island. Maybe a geological event isolated one of your species for a few millions years on an island, creating a giant/dwarf population which then expanded back on the continent.

A possible origin for this relationship could come from mutual protection. Maybe your world was a dangerous place in ancient times, and your small creatures required protection from their big brothers. On the other hand, while your big creature was well fitted for combat, they had difficulties getting rid of parasites that hanged on their tough skin. Your small creatures where happy to make a feast on these, and maybe this grooming tradition even perpetuated in their current society.

Who would hold the power in your society will largely depends on your creatures physiology, but it is likely that the smaller species would get an overwhelming advantage simply because they are smaller and then require less food. You could nerf this by making them dying much younger.

Answer 2

"The first Creature is bigger than the other"

There's your first problem. History is not kind to the smaller of two species that happen to occupy the same area. Especially if they compete for Food and Resources (which undoubtedly your species will).

The second problem is Intelligence.

See, a Lion and a Cheetah may exist on the plains of Africa and if they come into conflict, the Cheetah's only option is to run away - however the Lion isn't intelligent in the way that a Human is Intelligent. It doesn't have the concept of say... Going into the neighbouring Cheetah village and murdering all the Men and children and enslaving all the Women (We Humans can be right assholes). I mean, the interactions between 'normal' humans and the various pygmy peoples doesn't end well, in many instances, for the Pygmies.

And this is likely what will happen, unless there is no competition for Food/resources or there is a significant barrier between the two groups until such time that complex societies can evolve - then the likely scenario is essentially Genocide.

Bing Bong! Frame Challenge Time!

So, I mentioned a significant barrier and complex societies - If you look at the Europeans when they encountered other groups, if they lived in 'primative' tribal groups - it didn't go well. Whereas when they encountered say the Kingdom of Benin or China - societies with well-established Trade, then via mutually (if not often Immoral) beneficial arrangement - they could co-exist.

Let's assume then something like an Ocean between the two groups and due to reasons, both groups (like China and Europe) have both evolved large cities and complex societies and then one of them crosses the ocean and 'discovers' the other. If there are things which are mutually beneficial to trade, then it's possible the groups could co-exist...

But I want to stress - 'Possible' - the history of the world when two nations trade with each other but are just different racial groups (not different species) isn't exactly pretty.

Answer 3

Interesting question. The key is that you're looking for something comparable for sentient beings, rather than modern day animals. So, you can actually see situations anthropologically where various types of "Humans" co-existed for a decent period... until Homo Sapiens (specifically) entered the scene and appear to have committed genocide against all the others. There's a book by Yuval Harari called Sapiens, the first say quarter of the book has some interesting elements for you that discusses various contemporaneous Humans of (almost) similar sentience. But it was Sapiens who had some sharper sense of organisation, group think, coordination, and ... it seems ... blood-thirst and competitive nature. Outsmarting / out-everything all others, Sapiens ultimately come out on top (be it Neanderthals, Denisovans, etc). Harari's book covers a fair bit of ground and includes generalisations in parts, but I guess it's necessary in order to make the point he's trying to make. If you have a skim it could help you if you try to imagine a world where Sapiens never came into being, it might be argued that all the other 'Humans' could have co-existed a heck of a lot longer. The book posits that H. Sapiens are a bit of a fluke, and a such a rarity, that you could argue the probability of co-existing sentient beings of a common ancestor is much higher than what actually happened here on Earth (ie. Sapiens are such a fluke, and turned into what he describes as "ecological serial killers" in one part of the book, hahah). Anyway, just my 2 cents. Hope that helps. Though I agree with TheDemonLord's comment that the height differences are also going to present problem for you (especially if they compete for food).

Answer 4

While this is not extremely likely, there is a way it could work. The larger species would require more food and water. Making it difficult to migrate and explore. Thus the smaller ones moved out to another continent but larger ones could not follow. They developed separately in their own continents until such time they meet again in a more developed stage. After some wars, probably a few centuries of slavery, they could perhaps live together.