Far, far into the future, pretty much the entire Milky Way has been colonised by humans. The thing is that now the Empire has fallen, the technology of FTL travel has been lost in most places. Those who still have it are too busy fighting a war amongst themselves to be concerned with far-flung outposts.

Evolution has continued differently on different planets. Humans have evolved to fit the local conditions.

On the planet Schmell, there is a mutation that causes the human inhabitants all to have enormous feet while retaining pretty ordinary human proportions in every other respect.

Typically a six-foot male would have feet that are 2 ft (0.6 meters) in length.


What evolutionary or other pressures could plausibly cause this phenomenon and prevent it from dying out?


People still walk 'normally'.

Their feet are roughly twice as wide as 'normal' feet as well as twice the length.

The planet has been terraformed and can be considered very similar to Earth in most respects.

With the fall of civilisation on Schmell, the people still have memories and artefacts of the past but they are reduced to a pre-industrial style of living.

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    $\begingroup$ Given the widely disseminated myth about large feet, this may have been a case of sexual selection... $\endgroup$ – AngelPray Jan 15 at 22:01
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    $\begingroup$ Alternate, only-slightly-less-serious answer: to evade the shoe event horizon $\endgroup$ – Punintended Jan 15 at 22:28
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    $\begingroup$ Are these people amphibious? Feet that big might be an advantage under water $\endgroup$ – Dan Pichelman Jan 15 at 22:38
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    $\begingroup$ Why the downvotes? This is is a good question. $\endgroup$ – Renan Jan 16 at 5:17
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    $\begingroup$ Evolution takes a long time. A great deal more than the feet will have changed. $\endgroup$ – JBH Jan 16 at 7:18


While generally similar to Earth, Schmell's biosphere is mainly swampy. Its murky water is packed with organisms similar to phytoplankton, which humans harvest to fill dietary niches previously occupied by grains. There is also an abundance of zooplankton and many other larger species that dine on the phytoplankton.

Aquatic organisms are in such abundance in the nutrient-rich swamp that covers much of the planet that the water is more viscous than average. This confers an advantage to humans with slightly larger feet, who can swim better via biological swim fins. This selective pressure led to humans with much larger feet - thanks to Snell's lower gravity, they can use the liquid's surface tension to run on water, similar to the way the "jesus lizard" can on Earth.


Schmell gets the snow. Man, does it get the snow. You think it snows where you live? You should see the snow in Schmell!

To walk around on all the deep, white, frozen precipitation, it helps to be able to distribute your weight over a large surface area, that is, to have big feet. Small-footed people sink into the snow and are unable to continue their journey to market. Then they starve and die, and are thus rendered unable to pass along their genes any more. It's sad really, but there you have it.

As usual, let's present some parallels to the Real World (TM). Critters that live in snow tend toward big feet. The Eurasian Lynx comes to mind, along with the Arctic Hare, the Snowy Owl, the Polar Bear, the Adelie Penguin, and Nordic tribes-folk who invented these clever things:

Vintage Snow Shoes

  • $\begingroup$ That is a good idea. It could be extended to walking on other non-firm surfaces. $\endgroup$ – chasly from UK Jan 16 at 17:53
  • $\begingroup$ Indeed, this answer has some points in common with @punintended. Replace snow with soft, wet sand for example. $\endgroup$ – cobaltduck Jan 16 at 17:55
  • $\begingroup$ This is basically what I came here to post, saved me some typing :) $\endgroup$ – Tim B Jan 16 at 17:57

It could be only a case of genetic drift. When a small fraction of individuals remains far from the main population, a random genetic alteration could become common, even if it gives no advantage whatsoever (of course, it should also provide no disadvantage).
So, when the colony was small (maybe after the collapse of the Empire they had a crisis that left only a few hundreds people on the planet) one or two people had a random genetic alteration that gave them big feet. They transmitted this feature to their offspring (it is not a recessive feature), and in some generations, it became quite common.

  • $\begingroup$ Yes - that seems very plausible. I wonder if any creatures have actually evolved to have big feet for this precise reason. $\endgroup$ – chasly from UK Jan 15 at 22:34
  • $\begingroup$ I agree that genetic drift can explain neutral changes, or changes with very minor disadvantage. But feet doubling in size would very likely be disadvantageous in several ways, so they need another reason to persist in the population. $\endgroup$ – Milo Bem Jan 16 at 13:51

Back before the empire collapsed, the citizen of Schmell were a cantankerous bunch. This was partly due to fact that the empire tended to dump off its undesirables and unrepentant political dissenters on the world and forget about them. Often times someone would say something foolish, tactless or offensive. This lead to many conflicts, some expanding into global confrontation. Except for one group on a remote island. They were known to be wise and enjoyed relaxing on the beach or engaging in coastal activities. They were also known for a rather peculiar abnormality - big feet. After a rather devastating war the survivors came looking for these islanders with big feet to help them rebuild and learn wisdom in dealing with each other and accepting or at least tolerating their differences. When asked their secret the islander elders nodded wisely before answering. We islanders have big feet - we have learned to think before opening our mouths. We were forced to learn the hard way that its painful to stick your foot in your mouth. We often hurt ourselves as much as our foolish words harmed others and we concluded it was not safe or wise to continue in such a way. The visiting group were amazed at such profound knowledge and thanking everyone then left the island. But as they learned nothing; they eventually exterminated themselves into extinction leaving the planet Schmell to be repopulated by the big feet islanders.


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