I have a story in a mediaeval setting with no magic. There are elves, but they are essentially just absurdly long-lived versions of humans with pointy ears and somewhat more acute senses.

Unicorns are central to the story. They are roughly horse-shaped, though there is no need for them to be equids—in fact, I'm toying with the idea to give them cloven hooves. Naturally, they have long, fluffy hair and elegant spiral horns. I see no issues with any of that.

The problem is, they are fiendishly intelligent, on a par with people. That, too, is key to the story, but I just can't convince myself that animals that can't use tools and live fairly standard ruminant lives would evolve this kind of intelligence. Show me that I'm wrong, won't you?

  • $\begingroup$ I'm accepting Neil's answer, despite his scepticism--or because of it. Thanks to jknappen too. $\endgroup$ – Tumbislav Oct 31 '18 at 11:56
  • $\begingroup$ Please remember that we strongly encourage askers to wait at least 24 hours before accepting an answer. $\endgroup$ – Frostfyre Oct 31 '18 at 12:50
  • $\begingroup$ @Frostfyre I'll keep that in mind next time around. $\endgroup$ – Tumbislav Oct 31 '18 at 18:12
  • $\begingroup$ I thought unicorns had cloven hooves? $\endgroup$ – Brizzy Nov 2 '18 at 7:09
  • $\begingroup$ @Brizzy According to Zelazny, yes. According to Pratchett, no. Take your pick. $\endgroup$ – Tumbislav Nov 2 '18 at 7:30

The problem with this is that we only have humans to go on for human-level intelligence. There are many highly intelligent creatures including but not limited to primates, crows, dolphins, and octopodes.

If intelligence on this level is what you're after, then there is your proof that an animal can achieve that level of intelligence. For higher intelligence, we're forced to look at what it is believed to be the reasons behind human intelligence.

There are several theories regarding the importance of intelligence in humans during evolution.

Tree life

One theory being that in order to sleep in trees without falling out, we had to have higher brain functions. If our ancestors fell out of the trees, they could seriously injure themselves or get eaten by a predator. Bad things happened otherwise. Unicorns don't sleep in trees traditionally (though maybe yours do, but I'll assume that's not your case).


Another theory being that it was very much in the interests of survival to make friends and therefore be social. Higher brain functions are required to be able to recognize many faces and have many friends. If you had few friends which took care of you, eventually they may die off leaving you to fend for yourself, and being alone for the type of lifestyle which our ancestors had was a rough life to be sure. There was strength in numbers. Your unicorns may move in packs, but that's not quite the same as being social. They would need to be able to communicate in some fashion, perhaps using a highly sophisticated calling mechanism? Hmm, I'm not honestly convinced of this.


The traditionally believed reason behind modern human intelligence has been the usage of tools. In fact for a long time, it was believed the use of tools was a unique trait of human intelligence and what distinguished us from other animals. We now know this is no longer the case. Crows have been found to use sticks to obtain items out of reach, for instance. Although this isn't a unique trait, it could still be that the need for more advanced tools such as spears and knives meant the difference between being cold and hungry and being clothed and well-fed. Unicorns obviously cannot use tools, so I think we're also going to have to exclude this possibility.


Unicorns don't quite fit the description of these theories, and as such, none of the same conditions exist for a unicorn which existed for our ancestors. Though perhaps it is incorrect to base conclusions on the intelligence of human beings, however this is all we have to base ourselves with.

I hate to say it, but I'm in agreement with your sentiment that such animals could not have human level intelligence. It could be quite clever without being as intelligent as human beings, but it could never equal our intelligence without otherwise meeting some of these conditions in my humble opinion.

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    $\begingroup$ Birds manage to sleep in tree branches without the need for a human level of intelligence. I think we can rule this out. $\endgroup$ – Rekesoft Oct 31 '18 at 10:23
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    $\begingroup$ Thanks. The tribe argument is the one that works best in the context of my story. $\endgroup$ – Tumbislav Oct 31 '18 at 10:23
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    $\begingroup$ @Neil Birds sleep on trees by a simple locking mechanism of their claws. A bigger bird would need bigger claws on bigger branches. Several other animals, like leopards, also sleep on trees and are nowhere near human intelligence - and their intelligence is probably due to being carnivores much more than their use of trees for sleeping or eating. $\endgroup$ – Rekesoft Oct 31 '18 at 10:49
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    $\begingroup$ @Neil So what? I'm saying that being social and using tools may be reasons of the human intelligence - either cause or effect, probably both mixed - but I don't see why living on trees may be a cause (or an effect) for intelligence. I think that's just badly applied anthropic principle: since the order primates has given a lot of intelligent animals and these animals lived on trees, maybe there's a relation between them. And again, probably not. Correlation is not causation and I fail to see the link betweem these two. $\endgroup$ – Rekesoft Oct 31 '18 at 11:50
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    $\begingroup$ Untrained wild Elephants use tools, grasping with their trunk. Untrained wild Crows use tools, grasping with their beak. Untrained wild Dolphins use tools, grasping with their mouth. Unicorns have mouths, and like horses, a strong opposable jaw to crush, grab, pull or shake, and feet strong enough to shape objects on the ground, such as creating and using a lever from a branch. It is not obvious to me they could not use tools, hands are not a necessity. The intelligence and imagination to plan some minutes ahead is all any of them they need, given that, tool use will follow. $\endgroup$ – Amadeus Oct 31 '18 at 13:52

Intelligence has a lot of components, and there are driving evolutionary forces to increase them

  • Memory It is argued by evolutionary biologists that the complex fruit-based diet of primates requires a good long-term memory to remember where to find good food sources
  • Social structure Some intelligence is necessary to maintain a complex social structure.
  • Hunting Carnivores are usually more intelligent than herbivores
  • Language Having a language requires a lot of intelligence, but using it is evolutionary very efficient

Tools only come as an afterthought. Whatever their body allows, you may detect some tool usage on your unicorns (e.g., a stick handled with the mouth)

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    $\begingroup$ Hmm... if Unicorns in this world are to equines as elves are to humans, I wonder if it hurts the story for unicorns to be omnivores like humans (rather than herbivores like horses). This means they could hunt in packs (social structure) with the horn as their weapon. Now there's an evolutionary driver for the horn, too. That would mean a different jaw structure, which opens the door to language, and language in turn implies memory. $\endgroup$ – Joel Coehoorn Oct 31 '18 at 16:23
  • $\begingroup$ @JoelCoehoorn excellent suggestion, though I would like to add that horses already can and sometimes do eat meat. Best single article found w/a quick search (evidence is common once you know to search): horsetalk.co.nz/2012/04/17/horses-as-meat-eating-killers $\endgroup$ – Iiridayn Nov 1 '18 at 22:15

Why not make your "unicorns" carnivorous, tool users?

They hide their diet to keep the other intelligent animals from fearing them.

They manipulate tools using a long, forked, prehensile tongue (and shake "hands" when they greet each other).


This is a case of convergent evolution. An isolated population of humans or elves evolved into unicorns. We can imagine a very specific combination of environmental pressures selecting for traveling on all fours, hands and feet becoming hooves (as happened during the evolution of the modern horse), long, fluffy hair, and elegant spiral horns. It took a long time.

  • $\begingroup$ I suspect that such a specific set of circumstances could just as readily cause a decrease of intelligence. Thanks for the idea, but it wouldn't fit in my story. $\endgroup$ – Tumbislav Oct 31 '18 at 11:52
  • $\begingroup$ @Tumbislav We can add another environmental element which selects for intelligence... Sorry this idea doesn't fit your story. It's obviously far-fetched, I was really responding to Neil's answer, but didn't have the permissions to comment. $\endgroup$ – Davidides Oct 31 '18 at 12:02
  • $\begingroup$ Thanks. Like I said, yours is an interesting idea. I'll let it ferment at the back of my mind, maybe something will come of it. $\endgroup$ – Tumbislav Oct 31 '18 at 18:02

If they aren't necessarily equine, and can have things like cloven hooves, why not have prehensile hooves?

Prehensile hooves don't exist in the real world, as far as I know, but then, neither do unicorns. The moveable parts can be the actual hooves, or soft portions protected by the hooves as they walk, or a combination.

That being said, if elephants can be very social and intelligent, despite the inability to create or manipulate a lot of tools (sure, a fair bit with their trunks, but not much else)...and if marine mammals such as whales can also be intelligent, why not unicorns? Maybe an ability to really manipulate (or even create) tools will put them above the intelligent animals without that ability.

  • $\begingroup$ Good point. My real concern was the ruminant lifestyle, but it could be argued that both elephant and whale lifestyles aren't too different from that. The pressure in both those cases seems to be at least partly in navigating a difficult environment, e.g. finding the right waterholes in the right season in the case of elephants. $\endgroup$ – Tumbislav Nov 1 '18 at 16:56
  • $\begingroup$ Another marker of intelligence (though not universal) is midwifery. Elephants and some marine mammals do it. As do humans of course. $\endgroup$ – Cyn Nov 1 '18 at 17:00

You mention you're writing in a no (or low, anyway, depending on terms - given unicorns and long lived human "elfs") magic medieval-like setting. The medieval setting is well known for having a strong component of "magic" in history, in the form of religion (regardless of personal views on religion, it can be called a kind of "magic system" in fairness).

You could justify your world's unicorns by claiming that the "spirit" or "soul" is intelligent - the "software" as it were, while the body just provides the brain hardware to run or assist the intelligence. There should be ample room in the braincase for a human-like brain with full equivalence, etc. You'd just have to justify why a) some pre-mortal spirits ended up unicorns and some as humans, and b) why whatever deity or creation method created two species.

As other answers have stated, b) is somewhat difficult to justify with the "magic system" (again, sufficiently advanced science and whatnot, regardless of personal stance) of evolution, while with a neglectful creative intelligence you can say "she just likes unicorns and humans" and move on without impacting the story (or even mentioning it overmuch to the readers - the value is that you know the underlying causes in your world).

Edit: ah, didn't notice the "evolution" tag. Given that that "magic system" is presupposed, my answer might not be useful.

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    $\begingroup$ To readers - please do not downvote simply because I group creationism, religions, and evolution together as "magic systems". They are all proposed models for how the world works, and in an imaginary world which ones best explain the world is dependent on the author. $\endgroup$ – Iiridayn Nov 1 '18 at 22:33

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