Contrary to popular belief, Unicorns are not related to horses but instead are descended from the Siberian Unicorn.

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Over time:

  • their fur became whiter
  • they became slightly smaller
  • they have an above-average sense of sight (compared to other rhinos)
  • they started to develop a mane (optional)

Given these characteristics, how plausible is this and what evolutionary pressure would lead them down such a path?

NOTE: magic dose not exist in my story.

  • 2
    $\begingroup$ I imagine a prey animal like a horse/unicorn would have difficulty seeing straight forward due to lack of good depth perception. Maybe this animal is somewhat omnivorous and thus can aim a single spike compared to deer antlers which don't need much accuracy $\endgroup$
    – Dragongeek
    Feb 9, 2020 at 23:47
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    $\begingroup$ Do you mind return the rhino and you may keep the wig, thanks. $\endgroup$
    – user6760
    Feb 10, 2020 at 0:32
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    $\begingroup$ Easy to make a real unicorn: “Oh. Just a horse with an arrow in its head. Someone must have mistaken it for a deer.” — from Rozencrantz and Guildenstern Are Dead $\endgroup$
    – SRM
    Feb 10, 2020 at 3:03
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    $\begingroup$ If you can't find a good reason use nature classic answer: "The female like it!". It will even allow raindow tail like a peafowl. $\endgroup$ Feb 10, 2020 at 7:42

5 Answers 5


They could have evolved white fur coat if they had moved to a snowy climate, to blend in with the snow.

They also might evolve hooves because, like horses, having just one toe reduced the weight they had to carry at the end of each leg, making it easier for them to run and maneuver.

Evolving similarly to mountain goats could produce some cool traits.

  • Unlike horses, goats have hooves comprised of two split toes. (I thought two hoof-toes could be an interesting delineation between horses and unicorns) The toes can operate independently; the goat can use just one to gain purchase on extremely narrow surfaces, or splay the toes to gain more contact area. A cushy sole provides traction on sloped surfaces, and can deform inwards to absorb irregularities in the terrain.
  • Some mountain goats can also see movement up to a mile away.
  • Being smaller and lighter could help with climbing on weaker rocks.
  • 3
    $\begingroup$ This satisfies OP's other criteria too. You may want to edit this in: If there was less food available in the snowy tundra compared to their original habitat, there would be an evolutionary pressure on them to reduce their food requirements, satisfying OP's "they became slightly smaller". If they've had to become partly carnivorous (less plants growing in the Arctic!), they'd be hunting animals like Arctic hare that were also camouflaged against the snow - evolutionary pressure for better eyesight! The mane could be the result of increased hair growth to insulate them against the cold. $\endgroup$ Feb 10, 2020 at 8:05

Completely Plausible

Evolution has shaped the odd-toed ungulates into incredibly diverse forms, consider how different the ancient ancestors of the horse were, or how diverse the rhinoceros family was in the Eocene.

Every trait you gave for the Elasmothere descendant is rather straightforward, the fur can change due to environment or sexual selection, size can be reduced due to changes in available food or the climate, eyesight can be selected for, and manes are an easy example of sexual selection


They became arctic predators

Perhaps due to increasingly low temperature, or some other phenomena, the Siberian Unicorn's normal sources of nutrition started to die off, forcing them to turn to become omnivorous in order to survive.

If we assume they started eating meat as a large part of their diet, then the smaller size, arctic camouflage, and better eyesight make tons of sense.


Horses evolved to run. For a rhino to take on more horse-like proportions would probably require evolutionary pressure toward speed. Maybe a very agile predator that was good at getting behind the horn. Or a pack hunter, where if the rhino holds one off with the horn, two others strike its back. This might also force improved eyesight and snowy camoflauge.

The predator needs to be able to reliably penetrate the rhino's tough hide. Probably a very long claw or tooth.


You could also use the ladybug approach.

The unicorn is poisonous prey animal and wants to be seen. They develop white fur and glittery manes, put up a good fight, and when eaten, harms the predator. Predators learn that they are unpleasant to be around and avoid herds of them.


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