In a world I’m designing, a group of Homo Habilis or even Australopithecus Afarensis migrated into a northern Scotland environment becoming Trolls. These are not D&D trolls, but something else. and I was wondering what evolutionary pressures would lead to them? some basic characteristics these Trolls (with the help of Nicolai) include:

  • Never stop growing, even after they exit the growth spurt of juveniles and are capable of reaching 8ft in height
  • are bipedal
  • Have an average lifespan of 150-170 years (barring major injuries)
  • Have large noses
  • Are mostly covered in a thick, coarse hair. Like that of wolverines
  • have surprisingly human like eyes
  • Have orangutan-like strength
  • Have very rudimentary tool use
  • Have very sensitive eyes and are nocturnal
  • Their diet consists primarily of plant matter, though they scrounge a certain amount of protein from insects and carrion and will occasionally scavenge dead animals
  • They are not significantly prone to cancers
  • Are mostly solitary similar to orangutans but do form small groups during the colder months
  • males sing to attract mates similar to whales
  • Can fully regrow missing limbs in approximately 1025-1095 days (due to a stem cell based ability for continuous re-growth) similar to axolotls

Note: Magic does not exist in my world

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    $\begingroup$ You could think of a situation where small populations live separate from one another, where in each group only a single male lives with multiple females (much like gorillas do). Then add something akin to acromegaly to one of these populations and conjure up a reason why it would have significant benefits for that population. $\endgroup$
    – Bdrs
    Commented Mar 16, 2020 at 14:49
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    $\begingroup$ What leads to trolls? Too much bandwidth? Heh heh. $\endgroup$
    – puppetsock
    Commented Mar 16, 2020 at 15:02
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    $\begingroup$ @puppetsock Nope, trolls are older than 'too much bandwidth'. Instead see GIFT aka John Gabriel's Greater Internet Fuckwad Theory $\endgroup$ Commented Mar 16, 2020 at 15:31
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    $\begingroup$ @Demigan Hah! Too much stall width! $\endgroup$
    – puppetsock
    Commented Mar 16, 2020 at 17:02
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    $\begingroup$ everything but the regrowing limbs already existed in the hominids, (well the song thing could have occurred, we wouldn't know) in a mammal that takes it from possible to fantasitcal. $\endgroup$
    – John
    Commented Mar 17, 2020 at 2:50

2 Answers 2


Perhaps a combination of both evolutionary pressures and opportunities.

First, trolls really hate the sun. Perhaps there was a gene for xeroderma pigmentosum (allergic to the sun) in the small founder group, pushing them to be pretty nocturnal.

Thick hair is normal for a cold environment, or even for warm environments where the species doesn't need to run a lot (the human ability to cool itself while chasing prey is a huge evolutionary advantage).

Their diet and strength means there must be abundant, nutritionally dense plant matter in the area. Not that weak bamboo that pandas are always munching on. And if the plants tend towards being pretty tall, but not climbable (spiky or sticky or something), you are going to grow very tall to reach it (and be bipedal maybe). Heck, maybe they eat fungus that grows on the roofs of caves.

A large nose smells food and danger, easy advantages there (some theories suggest human's noses are are smaller and shaped downwards because we had ancestors that swam a lot, the aquatic ape theory).

Their ability to regrow limbs, live a long time, and not get cancer can all come from the same thing. What that thing is though is a bit tricky. Perhaps the plants they eat contain some property that increases bodily stem cells, thus increasing health and longevity. Or maybe part of the same mutation which caused the allergy to sunlight (which in Africa would have proved too fatal for the advantages to matter).

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    $\begingroup$ reading this make me imagining prehistoric sloth and axolotl combined. $\endgroup$
    – Li Jun
    Commented Mar 16, 2020 at 16:36
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    $\begingroup$ @LiJun I would love to meet that animal! $\endgroup$ Commented Mar 16, 2020 at 17:23
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    $\begingroup$ the "trolls being allergic to the sun" thing is an interesting idea and might explain the "trolls turning to stone in the sun" trope $\endgroup$
    – icewar1908
    Commented Mar 24, 2020 at 14:20

Almost all of these already existed in various hominids.

-high strength would be why their tool use is primitive they have not yet evolved the different muscle recruitment humans have that make for better fine motor control at the cost of weaker muscles.

-Large noses would be an adaptation to colder or dryer environments, however these places are not going to support an herbivorous primate, another explanation might be using the nose as a resonating chamber for their songs. Otherwise their behavior is not all that different from some early hominids.

Course hair is the primate norm.

the hominid line is known for bipedalism.

Long lifespan in large animals is not rare so this is fine, although it is harder if they are not social, you can just hand-wave this however.

To be big and old they will have to have more tumor suppressor genes just like elephants and whales do.

You could just use gigantopithicus and alter their noses and eyes, they are already huge herbivorous primates.

Problematic ones

Human like eyes is just a single mutation, chimps occasionally produce it. it is just a matter of making the sclera white. The problem is you can't have both human like eyes AND good night vision, the two are mutually exclusive. eyes like this are also not an advantage if it is not a social primate.

-never stop growing, this is hard in a mammal, but not impossible some mammals mammals (kangaroos) grow quickly to adulthood but then reach a point were they continue to grow but very slowly.

The hard stuff

-rapid regeneration, this is impossible in a realistic mammal, it just is not seen in endothermic homeotherms, so you are better using whatever handwavium you already have.

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    $\begingroup$ here a long nose monkey and this from tropical island/rainforest of borneo. $\endgroup$
    – Li Jun
    Commented Mar 17, 2020 at 4:28

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