# How small could humans be and develop a similar civilization?
**URL:** https://boards.straightdope.com/t/how-small-could-humans-be-and-develop-a-similar-civilization/997490
**Category:** Factual Questions
**Created:** [February 12, 2024, 8:43pm UTC](https://boards.straightdope.com/t/how-small-could-humans-be-and-develop-a-similar-civilization/997490 "2024-02-12T20:43:10Z")
**Posts on this page:** 20
**Page:** 1
### Author:  [@Hermitian](https://boards.straightdope.com/u/Hermitian)
#### Post date: [February 12, 2024, 8:43pm UTC](https://boards.straightdope.com/t/how-small-could-humans-be-and-develop-a-similar-civilization/997490/1 "2024-02-12T20:43:10Z")
How small could humans have been before it would really hamper development? An average of 4 feet tall? 2 feet? 1 foot?
The two things that struck me were:
1. Use of fire. This is pretty instrumental to staying warm (alive) and development of metallurgy. But fire does not scale up and down the same way. Small fire quickly goes cold. If people were like 1 foot tall, every useful fire is bonfire size and requires a lot of energy to maintain (normal trees to them would be equivalent to trees being 15 feet around to us and they burn up quickly).
2. Domestication of animals. Could we breed animals to be smaller? Cows and horses and goats are too large. This seems easier to overcome than #1.
I am sure there are many other factors that I am not thinking about.
---
### Author:  [@Mangetout](https://boards.straightdope.com/u/Mangetout)
#### Post date: [February 12, 2024, 8:47pm UTC](https://boards.straightdope.com/t/how-small-could-humans-be-and-develop-a-similar-civilization/997490/2 "2024-02-12T20:47:08Z")
Managing fire could still be done by smaller creatures, if they were able to develop techniques for handling it less directly than humans are able to; there is a bit of a bootstrapping problem in that though, because some of the better solutions for handling fuel and the fire itself, require the sort of tools that you only get if you have already solved the problem (i.e. metal tools, mechanisms, engines)
---
### Author:  [@DocCathode](https://boards.straightdope.com/u/DocCathode)
#### Post date: [February 12, 2024, 8:48pm UTC](https://boards.straightdope.com/t/how-small-could-humans-be-and-develop-a-similar-civilization/997490/3 "2024-02-12T20:48:13Z")
I recommend the classic Surface Tension- microscopic humans strive to reach the stars
---
### Author:  [@PhillyGuy](https://boards.straightdope.com/u/PhillyGuy)
#### Post date: [February 12, 2024, 8:59pm UTC](https://boards.straightdope.com/t/how-small-could-humans-be-and-develop-a-similar-civilization/997490/4 "2024-02-12T20:59:20Z")
This may relate to the Fermi Paradox — no link needed, I hope.
I think the evident rarity of industrial civilization, in this galaxy, indicates that everything has to be just so for it to develop. Too big, too small, too aggressive, too passive, wrong habitat, wrong number of limbs, etc., etc, and there’s no pathway to anything approximating us.
---
### Author:  [@Al128](https://boards.straightdope.com/u/Al128)
#### Post date: [February 12, 2024, 9:08pm UTC](https://boards.straightdope.com/t/how-small-could-humans-be-and-develop-a-similar-civilization/997490/5 "2024-02-12T21:08:44Z")
my stab at it:
it was mostly (Darwin’s) “fitness” (as in “survival of the fittest”) that made us the greatest species on earth, not muscular force …
so, chimpanse size (4ft?) should be sufficient. Probably a disadvantage in fringe climates, e.g. extreme north/cold or seafaring… but there was little competition in the extreme cold.
A good lateral Q: how big (size and weight) were humans (compared to today) some 2000/5000/10000 yrs. ago?
edit to add:
> **[Lucy (Australopithecus)](https://en.wikipedia.org/wiki/Lucy_(Australopithecus))**
>
> AL 288-1, commonly known as Lucy or Dinkʼinesh (Amharic: ድንቅ ነሽ, lit. 'you are marvellous'), is a collection of several hundred pieces of fossilized bone comprising 40 percent of the skeleton of a female of the hominin species Australopithecus afarensis. It was discovered in 1974 in Ethiopia, at Hadar, a site in the Awash Valley of the Afar Triangle, by Donald Johanson, a paleoanthropologist of the Cleveland Museum of Natural History.
> Lucy is an early australopithecine and is dated to about 3...
_Lucy was 1.1 m (3 ft 7 in) tall,[[19]](https://en.wikipedia.org/wiki/Lucy_(Australopithecus)#cite_note-19) weighed 29 kg (64 lb), and (after reconstruction) looked somewhat like a [chimpanzee](https://en.wikipedia.org/wiki/Common_chimpanzee)._
---
### Author:  [@TriPolar](https://boards.straightdope.com/u/TriPolar)
#### Post date: [February 12, 2024, 9:15pm UTC](https://boards.straightdope.com/t/how-small-could-humans-be-and-develop-a-similar-civilization/997490/6 "2024-02-12T21:15:06Z")
> [@Al128](#):
>
> it was mostly (Darwin’s) “fitness” (as in “survival of the fittest”) that made us the greatest species on earth, not muscular force …
So the force of our brains, right?
As long as these little humans had brains like ours they wouldn’t have faced any serious limitations.
---
### Author:  [@whc.03grady](https://boards.straightdope.com/u/whc.03grady)
#### Post date: [February 12, 2024, 9:51pm UTC](https://boards.straightdope.com/t/how-small-could-humans-be-and-develop-a-similar-civilization/997490/7 "2024-02-12T21:51:27Z")
The smaller humans had been, the more natural selection would have pressured them in totally different ways and the end result might not even look like a scaled-down modern human, let alone act and think like one. For example, two-foot tall humans would have been subject to predation much, much more often than actual-sized ones already were. They would have had to spend so many more physical and mental resources to avoid being eaten that who knows if they could have developed even ur-civilations at all.
Want to know what people’d be like if they were of a certain size? Look at what any existing primate that’s that size does and can do, and that’s probably pretty close to your answer.
---
### Author:  [@Chronos](https://boards.straightdope.com/u/Chronos)
#### Post date: [February 12, 2024, 10:06pm UTC](https://boards.straightdope.com/t/how-small-could-humans-be-and-develop-a-similar-civilization/997490/8 "2024-02-12T22:06:00Z")
But how much can you scale down human brains and still have them work as well? Or are you going with some completely different brain architecture (bird brains, for instance, seem to outperform mammal brains on a size-for-size basis)?
---
### Author:  [@GaryM](https://boards.straightdope.com/u/GaryM)
#### Post date: [February 12, 2024, 10:44pm UTC](https://boards.straightdope.com/t/how-small-could-humans-be-and-develop-a-similar-civilization/997490/9 "2024-02-12T22:44:08Z")
I believe I’ve read that years ago. Didn’t they have vehicles powered by amoeba like critters to break out of their world?
---
### Author:  [@DocCathode](https://boards.straightdope.com/u/DocCathode)
#### Post date: [February 12, 2024, 10:50pm UTC](https://boards.straightdope.com/t/how-small-could-humans-be-and-develop-a-similar-civilization/997490/10 "2024-02-12T22:50:47Z")
My copy is currently packed away. IIRC diatoms.
---
### Author:  [@Al128](https://boards.straightdope.com/u/Al128)
#### Post date: [February 12, 2024, 11:04pm UTC](https://boards.straightdope.com/t/how-small-could-humans-be-and-develop-a-similar-civilization/997490/11 "2024-02-12T23:04:01Z")
> [@Chronos](#):
>
> But how much can you scale down human brains and still have them work as well?
good point … women’s brains are 10-15% smaller (vol) than mens’ … to no evidently adverse effect. Similar kids’ brains are way smaller, but outperform on many levels (e.g. language learning) adult’s brains.
Also there is “little people” (don’t know what the right expression is nowadays) who seem to just be as smart as regular people.
- **Jyoti Amge:** Holds the Guinness World Record for the shortest woman living at 62.8 cm (2 ft 0.72 in). She’s an actress and motivational speaker.
IIRC, there is a lot of wasteland in our brains (grey matter?) … that could evolutionary be trimmed down and as long as you keep a similar amount of ganglies and synapses, it should be able to scale down
so my uneducated guess - there is enough leeway in our brain-sizes to do pretty much the same in a way smaller container.
---
### Author:  [@Chronos](https://boards.straightdope.com/u/Chronos)
#### Post date: [February 12, 2024, 11:11pm UTC](https://boards.straightdope.com/t/how-small-could-humans-be-and-develop-a-similar-civilization/997490/12 "2024-02-12T23:11:22Z")
On the other hand, if our brains could be smaller, why aren’t they? They’re already big enough to cause significant problems (for instance, there are a lot of complications in human childbirth due to the size of our heads), so the selection pressure would be there. It seems like, if there is a brain design that would work just as well as ours, it’s something radically different, that can’t be reached from here via incremental changes.
---
### Author:  [@GaryM](https://boards.straightdope.com/u/GaryM)
#### Post date: [February 12, 2024, 11:43pm UTC](https://boards.straightdope.com/t/how-small-could-humans-be-and-develop-a-similar-civilization/997490/13 "2024-02-12T23:43:12Z")
Yes, that’s it.
---
### Author:  [@beowulff](https://boards.straightdope.com/u/beowulff)
#### Post date: [February 13, 2024, 1:03am UTC](https://boards.straightdope.com/t/how-small-could-humans-be-and-develop-a-similar-civilization/997490/14 "2024-02-13T01:03:11Z")
What, you think another civilization could detect US?
---
### Author:  [@Andy\_L](https://boards.straightdope.com/u/Andy_L)
#### Post date: [February 13, 2024, 1:10am UTC](https://boards.straightdope.com/t/how-small-could-humans-be-and-develop-a-similar-civilization/997490/15 "2024-02-13T01:10:56Z")
Earth life might be detectable from as far as 100 ly away ([Are Aliens Visiting Earth? - #415 by Andy\_L](https://boards.straightdope.com/t/are-aliens-visiting-earth/912949/415)) - but of course that’s a tiny fraction of the galaxy, let alone the universe.
---
### Author:  [@Lumpy](https://boards.straightdope.com/u/Lumpy)
#### Post date: [February 13, 2024, 1:46am UTC](https://boards.straightdope.com/t/how-small-could-humans-be-and-develop-a-similar-civilization/997490/16 "2024-02-13T01:46:56Z")
I think one-meter tall would be about the limit; below that women would have had too much difficulty giving birth to children large-brained enough to be of modern intelligence.
---
### Author:  [@Tibby](https://boards.straightdope.com/u/Tibby)
#### Post date: [February 13, 2024, 2:02am UTC](https://boards.straightdope.com/t/how-small-could-humans-be-and-develop-a-similar-civilization/997490/17 "2024-02-13T02:02:34Z")
Well the Cheela from Dragon’s Egg were the size of sesame seeds. Of course they lived on a neutron star, with a surface gravity 67 billion times that of Earth. Might not be possible on Earth.
---
### Author:  [@PhillyGuy](https://boards.straightdope.com/u/PhillyGuy)
#### Post date: [February 13, 2024, 2:02am UTC](https://boards.straightdope.com/t/how-small-could-humans-be-and-develop-a-similar-civilization/997490/18 "2024-02-13T02:02:45Z")
> [@beowulff](#):
>
> What, you think another civilization could detect US?
Our galaxy is 100,000 light years across, so it’s unlikely they could detect us yet. Even if an automated probe already has detected us, it would probably take many thousands of years for the news to be delivered.
---
### Author:  [@FlikTheBlue](https://boards.straightdope.com/u/FlikTheBlue)
#### Post date: [February 13, 2024, 2:12am UTC](https://boards.straightdope.com/t/how-small-could-humans-be-and-develop-a-similar-civilization/997490/19 "2024-02-13T02:12:59Z")
What about vehicles? Would scaled down ships, cars, and planes for one foot tall humans be practical for long distance travel? What if we were even shorter than that? Ocean going ships in particular seem like they would suffer significantly if they were of smaller size.
---
### Author:  [@Al128](https://boards.straightdope.com/u/Al128)
#### Post date: [February 13, 2024, 2:29am UTC](https://boards.straightdope.com/t/how-small-could-humans-be-and-develop-a-similar-civilization/997490/20 "2024-02-13T02:29:54Z")
good Q, @Chronos …
any idea on the Q: how has the headsize (circumference) evolved vs. general body size … say over the past 1000-3000 years?
we know pretty good that the 2024 people are way taller/biger than the 1424 people (armour), etc…
but how about head-size? … maybe our head-size did also grow over the past 500 years - but below avg (compared to the rest of the body) … just a (unfounded) theory
[Next page](https://boards.straightdope.com/t/how-small-could-humans-be-and-develop-a-similar-civilization/997490.md?page=2)