Various scenarios that put more or less every folks in space for extended periods of time in microgravity in the future have been proposed, mostly based on space but there could be colonization scenarios as well. Yes artificial gravity is also proposed in some cases, but for the purpose of this question let's stick to .

Question: What animals would be best suited as pets or comfort animals for extended periods of spaceflight in microgravity?

From How would a mousetrap for use in space work?

Screenshots from "Mice aboard the International Space Station" https://www.youtube.com/watch?v=q7lgj3aZ8dU

Screenshots from Mice aboard the International Space Station

See also If mice escaped on the International Space Station, could they live and thrive?

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    $\begingroup$ answer: none. Bad, bad, bad, bad idea. $\endgroup$ Jul 22, 2021 at 8:25
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    $\begingroup$ @PcMan The previous comment is a reminder that the question post does not ask "Do you think it's a good idea if..." specifically because opinion-based answers are not a good fit in Stack Exchange. Answers can be written based on known animal biology and physiology and draw from a huge knowledge base of how well which animals adapt to space. $\endgroup$
    – uhoh
    Jul 22, 2021 at 9:31
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    $\begingroup$ Crickets. They make nice sounds, don't eat much, reproduce fast, and you can eat them. $\endgroup$
    – Ng Ph
    Jul 22, 2021 at 9:36
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    $\begingroup$ Given how fast mice can move & how they can be a problem if they escaped, maybe a sloth. $\endgroup$
    – Fred
    Jul 22, 2021 at 16:36
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    $\begingroup$ I've seen (and, talked to) these guys at space-oriented trade shows - they'd like to interest long-duration astronauts in their product... $\endgroup$
    – Digger
    Aug 22, 2021 at 18:44

3 Answers 3


Logistics sets some applicable limits:

  • Animals require food, produce waste. The larger the animals, the more resources required. In an environment where every gram is expensive, this means animals should be small.
  • Something with a will on it's own moving among critical equipment is hard to plan for. Animals should therefore be confined to their own environment. Since space on a spacecraft is limited, this environment has to be small.

Fish, insects, maybe mice, anything that's small, low maintenance, and can live in a small habitat. Aligns pretty closely to a pet you would trust a young child with.

But again, if strictly just for comfort, human interaction seems to sufficiently cover the social needs of humans. So perhaps no pets at all?

  • $\begingroup$ I'd probably go with fish over mice, because if fish escape the habitat, they will die. If mice escape, they may die. $\endgroup$
    – notovny
    Oct 13, 2021 at 14:30
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    $\begingroup$ Escaped fish don't chew on cables. $\endgroup$ Oct 13, 2021 at 19:29
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    $\begingroup$ +1 for small! However, many people would disagree with you on this one: "human interaction seems to sufficiently cover the social needs of humans." Interacting with humans is complex and stressful for many, while interaction with animals can be much more relaxing. There is a lot of scientific literature showing the positive effects of therapy dogs. $\endgroup$ Oct 14, 2021 at 18:34
  • $\begingroup$ @WaterMolecule indeed! That Canis familiaris and Felis catus${}^1$have evolved to be distinct species, and the sheer number as registered pets today (where this is implemented) and the industry built around feeding and entertaining them (and designing space toilets for them) attests to this. $${}$$ ${}^1$to be inclusive :-) $\endgroup$
    – uhoh
    Oct 14, 2021 at 22:54

Cats, dogs, mice or rabbit as pets in zero gravity would be a problem, training them to use a zero gravity toilet would be at least very difficult if not impossible. Similar problems with eating and drinking.


I would be fascinated to see how something like a sugar glider or flying squirrel would do in microgravity. Tiny, omnivorous, and can be kept as pets. I wouldn't be surprised if they could eventually figure out how to use their gliding membranes to fly/swim/otherwise move around.


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