The usual characterization of humanoids from high gravity planet is that they are stockier with thicker bones and larger muscles and this assumption isn't far fetched. Heavy animals on earth have pillar-like legs and enormous muscle groups to move themselves. However, creatures built like this don't develop tool-using hands since they need all their appendages to support their immense bulk. In order to accommodate the ability to support all of one's weight on two legs instead of requiring four, wouldn't the mass of humanoid need to be lower and therefore smaller?

Higher gravity would be between 1.5G and 3.0G compared to Earth.

Would a humanoid from a high gravity planet be smaller than humans on Earth? By this same logic, would it hold that humanoids from lower gravity planets also potentially be larger than us?

  • $\begingroup$ Related. $\endgroup$
    – HDE 226868
    Dec 19, 2016 at 15:51
  • $\begingroup$ I recall reading a book where the high-grav alien was actually stick-thin. $\endgroup$
    – nijineko
    Dec 20, 2016 at 21:26
  • 1
    $\begingroup$ Re two legs vs four, have you perhaps forgotten about tyrannosaurs? Estimated weight 9,900 – 31,000 lbs, per Google, got around on two legs just fine. $\endgroup$
    – jamesqf
    Dec 14, 2019 at 3:48

2 Answers 2


Your assumption that "creatures build like this don't develop tool-using hands since they need all their appendages to support their immense bulk" is false.

Elephants, for example, use their trunks to paint, play instruments, etc. (once we teach them how to, anyway). Maybe given a few more hundreds of thousands of years they too might have evolved to a higher intellectual niche, just like our own ancestors did.

There's no reason why a creature from a heavy gravity world might not develop limbs specifically meant to manipulate tools.

Now, as to being "smaller" than us, they may very well be shorter, however they may be quite massive depending on their other proportions.

  • $\begingroup$ Also, many Earth mammals happen to have a quadruped body plan, but that's not the only one you'll find even likely right in your own home, let alone on our planet. Higher gravity may favor different body plans. $\endgroup$
    – user
    Dec 19, 2016 at 19:38

If you humans colonized a slightly higher gravity world they would likely get shorter, especially after a few generations they would also get wider more stocky as bones get thicker and muscles get larger. not due to weight but due to selective pressure caused by high blood pressure and fluids pooling in the feet. the shorter you are the smaller the fluid column in the body and hte less pressure on the body fluids there is. They would also end up with larger hearts as it fights to move blood into the brain. they would also end up with a lot of vascular problems, more hemorrhoids, and die early.

At 3X earth gravity humans would not survive on the surface for long.

A humanoid that evolved on the planet would not have these problems as it would already have adaptations to deal with it.


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