Solitary humanoids aren't uncommon in works of fantasy/cryptozoology with Bigfoot coming to mind. What I want to know is What evolutionary pressures would lead to solitary humanoids? Some characteristics of my solitary humanoids include:

  • being 7 feet tall
  • have human-level intelligence
  • are mostly solitary similar to orangutans
  • are mostly bipedal but can run on all fours while running
  • are omnivorous
  • are diurnal
  • Are mostly covered in a thick, coarse fur. Like that of wolverines
  • are 3 times stronger than humans
  • have sharp claws (optional)
  • have a stronger sense of hearing and smell
  • have proportionately longer arms
  • can interbreed with humans but the resulting offspring are always infertile similar to mules (optional)
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    $\begingroup$ Marine life is the way to go $\endgroup$
    – user75689
    Commented May 29, 2020 at 15:13
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    $\begingroup$ Living in water allows animals to grow sizes they would not be able to sustain on land, thats why when out of the water they drop on all four. Cold water selects for the people with longer body hair (humans have as many body hairs as monkeys but thinier and shorter) $\endgroup$
    – user75689
    Commented May 29, 2020 at 15:16
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    $\begingroup$ As you have pointed out Orangutans as an example of your model solitary behavior ("solitary but social" is how Wikipedia describes them), surely the same evolutionary pressure apply. I suspect the answer is not evolutionary pressures forcing them to be solitary, but a lack of pressures forcing them to knit more closely together in larger social groups. $\endgroup$ Commented May 29, 2020 at 15:26
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    $\begingroup$ "have human-level intelligence" - do you want full intellectual development or just the capability? In solitary individuals, I'm afraid, the speech may not develop at all. $\endgroup$
    – Alexander
    Commented May 29, 2020 at 16:32
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    $\begingroup$ Except for the height, hair, and claws, you've pretty well described me :-) Seriously, quite a few humans fit the "solitary but social" model, and a few are even anti-social. $\endgroup$
    – jamesqf
    Commented May 29, 2020 at 16:53

2 Answers 2


We're looking at something peculiar here. The claws are what make me question a "it's a giant chimpanzee" approach,since the reason primates have nails instead of claws is that they got in the way when wrapping the hand around branches.

I won't lie here, but the main problem is: being able to breed with a human means a relatively recent ancestor to the point not enough genetic differences have accumulated to make a hybrid between the 2 completely impossible. In here though, we have a creature which, despite being a very close cousin to the point of having human-level intelligence (possibly separated during the first hominids, with my main guess being the Neanderthal period), has traits lost long before the first hominids. While this could be blamed on it re-evolving, I find this to be the most problematic trait in here.

Other than that, all other traits seen very easy to occur. In fact, apart for "human level intelligence" in the sense of being exactly like a human and "able to breed with humans", your creature basically resembles a bear in many ways (tool using, believed to have a sense of self conscience and being able to recognize itself, good sense of smell and hearing, engages in grieving, stronger than a human, dense fur coat, relatively solitary, seem to have a sense of beauty, will actively get high with jet fuel if given the chance in the case of the bears from Russia, etc). I'd even risk saying it is an omnivorous cousin of the short faced bear, which, due to pressures similar to the first primates, began adapting to a more bipedal stance and evolving opposing digits on its hands, with the claws still being used to more branch-less trees and thus being kept and the arms becoming longer to aid in climbing, all other factors basically match what you want (please understand that if you want it to breed with humans, it can't be that different from a giant chimpanzee, just look at how horses, zebras and donkeys look alike; with the same happening to tigers and lions, which can also have hybrid offspring).

  • $\begingroup$ Horses and donkeys don't look at all alike. $\endgroup$
    – jamesqf
    Commented May 29, 2020 at 16:57
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    $\begingroup$ @jamesqf Their skeletons are hard to tell apart for someone who's not a specialist, their muscular system is very similar and so is their genome. Also I didn't mean "look alike" as "being an exact copy when looking from the outside", just look at chimpanzees, which are 99% similar to us on the genetic level (or at lions and tigers, which are also easily distinguishable when looking just at how they look). I mean that it won't have traits too different, like the presence of claws. $\endgroup$ Commented May 29, 2020 at 17:19
  • $\begingroup$ I admit to preferring my horses living, but I would think size ought to be a pretty good clue as to whether a skeleton belongs to a horse or donkey. Genetic similarity is of course required, but it's not necessarily reflected in appearance. $\endgroup$
    – jamesqf
    Commented May 29, 2020 at 20:02
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    $\begingroup$ @jamesqf that's exactly what I said regarding the human-chimpanzee and the lion-tiger comparisons. Regarding the donkeys and horses, I'm referring to overall anatomy and skeletal structure rather than size of bones. $\endgroup$ Commented May 29, 2020 at 20:06
  • $\begingroup$ What you said is that horses and donkeys look alike, not that there are anatomical similarities when you dissect them, or that they are genetically similar. If you have ever seen horses and donkeys, you should realize that they don't look all that much alike - no more than say horses and deer. $\endgroup$
    – jamesqf
    Commented May 31, 2020 at 3:14

Asocial behaviour is heavily correlated to testosterone. And excessive testosterone is heavily correlated to people surviving hard situations.

It is unknown if slavery, rape, war, almost starving to death or being on the edge of death daily causes people to produce more testosterone to have better chances to survive or if only people with naturally higher testosterone survive when being victims to these situations while people with normal testosterone die.

Regardless, putting a certain population through extreme situations for millenia or even centuries could cause this population to evolve an extremely high amount of testosterone.

(Yeah I said centuries, evolution can be incredibly fast)

Testosterone increases strength, size, density of body hair, asocial behaviour and various other things.

This satisfies all your requests for that specific humanoid except claws.

Humans can't have claws.

As for running on four limbs, most kids do that...and some stupid adults do that too...mostly because they don't know how to run on only two limbs.

And well, testosterone is kind of correlated to stupidity.


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