Suppose humanity manages to terraform Mars: we give it a magnetic field, an atmosphere, then Mars gains oceans, lakes and rivers and we plant forests there.

So now Mars looks like another Earth and people have already colonized it. I was wondering though, after we colonize Mars we would bring animals over there.

I already know that we would have to bring insects, like bees, to pollinate plants, but what I'm referring to is wildlife: like lions, deers, sharks, whales etc. Suppose we have a way to get animals there with ease, I am wondering if there is an interest to bring the biodiversity of Earth to Mars as well, and truly make Mars a second Earth.

(Edit by MichaelK)

Is there anything that prevents Mars to be used as a wildlife habitat for higher order species that originally evolved on Earth?

  • $\begingroup$ There are so many books one could write with this premise. From "wasted chances and cheap tourism planet" to "wildlife with technology ban". What will humans do in your book is entirely up to you to decide. $\endgroup$
    – Mołot
    Aug 11, 2018 at 14:42
  • 1
    $\begingroup$ @JohnMichailidis , as a general hint (to you and everyone reading this)... whenever a question is of the sort "Can [feat] be done?"... the best way to solve this is to flip the question around: "Is there anything that absolutely, with certainty prevents [feat] from being done?". If the answer is "Yes", the answer to the original question is "No, it cannot be done". But if the answer is "No, there is nothing that prevents it", then the answer to the original question is "Yes, it can be done". $\endgroup$
    – MichaelK
    Aug 11, 2018 at 15:56
  • $\begingroup$ @John Michailidis I have an answer to this question: worldbuilding.stackexchange.com/questions/119739/… That mentions the possibility that a fraction of the artificial space habitats made in the future would be used as wildlife sanctuaries. $\endgroup$ Aug 11, 2018 at 17:42
  • $\begingroup$ @MichaelK I can edit it to state as such if you like, but I guess it's up to the OP. $\endgroup$
    – SealBoi
    Aug 11, 2018 at 17:45
  • $\begingroup$ Considering how much it would cost to terraform Mars, I doubt they are just going to make it a wildlife preserve $\endgroup$
    – Starpilot
    Aug 11, 2018 at 18:17

2 Answers 2


First of all, you might want to know that it isn't really as simple as "We put plants there, now we can start on animals." The introduction of plants would have to be in tandem with the introduction of certain fauna and microbes.

So, here's a step-by-step plan of how I think you should do this:

  • You land on Mars, which has been given a habitable atmosphere and oceans, but that's all. Stay in the landing crafts for a while, farming high-density algae and termites. Explore the surroundings.

  • Assuming the landers can work as habitation complexes for the time being, use waste from the farming to prepare some kind of makeshift soil. Plant some kind of resilient (ideally edible, so it can be used as a food source temporarily) plants in the soil, along with earthworms (Vital) and some insects that don't harm the plants.

  • Begin to plant more and more plants, but ideally resistant ones. Transgenic plants would also be a good idea. Food is also a priority, so food plants are still good.

  • This is where the terraforming begins proper. Spread lichens and soil fauna where soil isn't already present. Introduce algae to the oceans, and drill boreholes or coat the ice caps in dark algae to make it warmer. Introduce some kinds of fast-growing trees and other varieties of plants, and breed the smallest vertebrates out in the open.

  • Now you can start making it look more like a wildlife reserve. Slow-growth trees can be planted, and thaw the cryo-preserved embryos of large animals.

Now, here's what to do with the wildlife:

This is actually quite a lot like Pleistocene Park, a proposed solution to thawing permafrost in Siberia. The project plans to convert tundra into grassland by introducing large megafauna. From Wikipedia:

In present-day Siberia only a few of the former species of megafauna are left, and their population density is extremely low, too low to affect the environment. To reach the desired effects, the density has to be raised artificially by fencing in and concentrating the existing large herbivores. A large variety of species is important as each species affects the environment differently and as the overall stability of the ecosystem increases with the variety of species. Their numbers will be raised by reintroducing species that went locally extinct (e.g., muskoxen). For species that went completely extinct, suitable replacements will be introduced if possible (e.g., wild Bactrian camels for the extinct Pleistocene camels of the genus Paracamelus). As the number of herbivores increases, the enclosure will be expanded.

While this is taking place, the effects will be monitored. This concerns for example the effects on the flora (are the mosses being replaced by grasses, etc.), the effects on the atmosphere (changes in levels of methane, carbon dioxide, water vapor) and the effects on the permafrost.

Finally, once a high density of herbivores over a vast area has been reached, predators larger than the wolves will have to be introduced to keep the megafauna in check

So, basically: herbivores first. Just like in Pleistocene Park, release a few herbivores into an enclosure, expanding that enclosure as their numbers rise. If they overpopulate, you'll have to play predator and shoot a few, sadly.

Then, as the herbivores reach the desired density, slowly begin to introduce large carnivores like wolves, big cats, sharks, etc. Eventually, you'll have a fully functioning ecosystem.

As for what animals could live there, as long as you tailor the environment to their needs, pretty much anything. Like I said, coating the ice caps in dark-coloured algae will significantly increase the temperature; whatever temperature you make it, whatever wildlife that can tolerate can live there.

To get these optimal conditions, however, you'd have to alter the atmosphere from orbital platforms, and somehow seed the planet with oceans from space as well, so that the first landers can begin terraforming.


As long as you do it right, you can give Mars any climate and atmosphere you like. Introduce herbivores first, with heavy human intervention, and then introduce carnivores gradually.


Terraforming doesn't change the nature of the planet

Mars is smaller than Earth and more distant from the sun. That makes it colder, with less light, and with a thinner atmosphere even with assistance. You could bring some animals over, but not all.

Once terraformed, Mars would work very well for these kinds of direct imports:

  • High altitude fauna.
  • Cold desert fauna.
  • Arid oceanic coastline fauna.
  • Water life (I think, there would be a difference in surface water pressure that might cause problems).
  • Limited avian life, restricted to high-altitude and cold climates.

Now, you might be tempted to look at something like Lake Sevan in Armenia, considered the highest alpine lake in the world, and consider its ecology. However, at only 2Km above sea level, it's likely not high enough in altitude to effectively mimic a terraformed Martian ecosystem. But it's a start.

As an aside (in case you were considering it), Due to the lower sunlight, colder climate, and thinner atmosphere, Mars would make a poor farming/ranching source for Earth. Of course, anything would help, but just the more sparse post-terraforming food supply would limit the quantities and sizes of animals you could import. A jungle ecology would be impossible, I'm afraid. I even doubt a savannah ecology could survive without considerable human intervention.


Yes, for a limited amount of wildlife, Mars could be used as a reserve.

  • $\begingroup$ By the way, in my answer, I suggested coating the ice caps with black algae and drilling bore-holes to increase the temperature. With appropriate future technology, artificial gravity might work. Also, some kind of giant orbital mirror could brighten up the sunlight. I'm not sure what to do about the thin atmosphere though. $\endgroup$
    – SealBoi
    Aug 12, 2018 at 11:48
  • $\begingroup$ @SealBoi, That's a lot of expensive tech just to create a wildlife preserve. While the OP didn't put any limits on the application, eventually economics win out over utility. It would be cheaper to solve the problem here on earth than to apply planet-wide aritifical gravity and solar mirrors so large they acted as extra suns. $\endgroup$
    – JBH
    Aug 12, 2018 at 12:37
  • $\begingroup$ Indeed, yes. Still, I could see this happening on some other Mars-like planet in some future interstellar empire where humans already inhabit countless world's. $\endgroup$
    – SealBoi
    Aug 12, 2018 at 13:03

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