Assume that the life in question is similar to what appeared in the Mesozoic Era of Earth. What would be fundamental differences between their ecology and anatomy compared to Earth life, due to the increased gravity?

For context, the planet I am imagining is ~4 times the size of Earth and has ~3 times its gravity. Additionally it has Earth-like properties with the necessary atmospheric conditions for the Earth Mesozoic Era to occur.

Edit: That was too broad of a question and I have since reviewed the topic so to be specific I was worried about how things such as hunting and foraging by animals that evolved into miniaturised versions of the fauna seen on Earth (but not the exact same fauna), be affected?. Given that the implications of high-gravity Earth (HGE) fauna development encompass a wide range of variables, with Turner even suggesting the more likely mode of movement might be rolling or sliding, this question is still too broad.

I assume the plant life that succeeded on this planet would be similar to vines and bushes as they spread out along the ground gaining as much surface area to the sun, while lowering the pressure on itself by sticking close to the ground. However I imagine if trees did develop on this HGE they would not be too tall and have incredibly thick bases that were very stout.

So the question becomes: On land, would carnivores, herbivores or omnivores be more viable on a HGE given the increased metabolism requirements? Would plant life even bare fruit due to the increased energy requirements of high gravity (calling into question the validity of herbivores on land)?

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    $\begingroup$ I am not downvoting, but this is way too broad. Seems like you are basically asking us to describe way too much of your world. "Ecology and anatomy" are huge swaths of a world. $\endgroup$
    – user11864
    Commented Jul 7, 2016 at 16:44
  • $\begingroup$ Okay so you want tiny dinosaurs? :P I assume by your meaning you want at least something specific from the mesozoic era (plants/animals/general aesthetic) but you want it to be smaller and stockier in stature (due to the stronger gravity). $\endgroup$ Commented Jul 7, 2016 at 19:46
  • $\begingroup$ I am sorry about that, I will strive to keep the questions specific in the future. $\endgroup$
    – Flatmoot
    Commented Jul 7, 2016 at 23:31

1 Answer 1


Though Agapwlesu is correct in that this is a very broad question, I'll try to give you something to get started on.

We'll start as broad as it gets: the overarching ecology. A High-Gravity-Earthlike (HGE) would largely just be a compressed version of our Earth. The plants and "trees" would not stretch very high, roughly one third as high (due to increased energy to transport water any higher). By the same effect, tunneling species would likely opt for caves over digging their own burrows for fear of them collapsing under increased stress. So all in all, life remains at or near the surface of the land. That said, aquatic life may flourish relative to land life. Without concern for the stressful effects of high gravity, water-based life would likely be unchanged, possibly even better off, I really can't hazard a guess between the two though.

Anatomically, the creatures would mimic their landscape. Many squat, dense organisms would be present over anything too long or thin. An exception to this rule may be that a sufficiently light organism could maintain a lithe physique, but expect more rhinos than giraffes. Bones would be incredibly dense (unless the extremely light exception is in effect), and muscles would be equally toughened not only for movement, but to just keep intestines where they're supposed to be. We might see some creative forms of movement, such as more sliding or rolling organisms, as picking up leg(s) for every step quickly becomes costly.

The diet and environmental needs of said organisms would be immense. Luckily for us, atmospheric composition is disputed enough for the Mesozoic Era that we can handwave our way to a higher-than-normal oxygen concentration for our HGE, and justify the incredibly difficult lifestyle with it.

For future reference, please do try to narrow things down a bit, maybe ask about a specific features of the HGE: "How would organisms' bones be formed?" "What plant heights may we expect?" etc. It's honestly better for you to do it this way as more questions means more links to get you the answers you want!


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