The SciNews video Mice aboard the International Space Station is fun to watch for those tired of the same old rocket launch videos.

Behavior of mice aboard the International Space Station

20 female mice were transported to the International Space Station by SpaceX CRS-4 Dragon spacecraft. On NASA’s Rodent Habitat, the mice engaged in a full range of species-typical behaviors. After 7–10 days, younger mice began to exhibit distinctive circling or ‘race-tracking’ behavior that evolved into coordinated group activity. This activity may represent stereotyped motor behavior, rewarding effects of physical exercise, or vestibular sensation produced via self-motion.

It looks like they've figured out how to move around and even get plenty of exercise, but these are just short video samples.

Question: How well do mice manage in space over extended periods of time. Do they exhibit symptoms of serious stress and become dysfunctional, or do they adapt and live fairly healthy lives? This group was single-sex, but if a mixed group were brought to space could they reproduce? Could rogue escaped mice end up inhabiting the ISS and becoming established multi-generational co-occupants, assuming someone made food and water available?

Mice on the International Space Station

About half-way through they really get moving!

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    $\begingroup$ They've got wild staring eyes, they've got a strong urge to simulate gravity, but they've got nowhere to fly to fly to fly to $\endgroup$
    – qq jkztd
    Apr 16, 2019 at 12:15
  • 1
    $\begingroup$ @qqjkztd The SE UI should provide a separate field for related song tagging, a system of reputation, badges, the works! $\endgroup$
    – uhoh
    Apr 16, 2019 at 13:38
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    $\begingroup$ Depends, are they PS/2 mice or USB? $\endgroup$
    – Vikki
    Jul 22, 2021 at 0:33

1 Answer 1


I'm going to take this one medium-seriously. The mice can clearly figure out how to clamber about in microgravity, and they also are seen eating so I assume they could take care of their basic needs if sustenance were available. I have no information to support this but I feel like they would figure out the copulation aspect too. "Life, uh, finds a way." So let's look at some problems our intrepid rodent friends might face:

Direct Obstacles of Microgravity

  • We know humans experience myriad physical symptoms of extended spaceflight including decreased muscle mass, decreased bone density, higher risk of cancer (possibly for ISS astronauts), changing in the shape of the eyeballs, etc. Since we use mice as proxies for human experimentation quite often, let's assume they can turn the tables and expect to experience some/all of these symptoms based on our experience. These issues may not critically endanger the mice (especially over a shorter lifespan), but they will not be happy upon possible return to Earth.
  • Humans can reason through the obstacles of movement in microgravity. The station is also designed for humans to move around easily and astronauts are trained in doing so. Even though the mice clearly figure out how to move around in a small space, I wouldn't envy being the mouse trapped floating in a large open area. Without human size or intelligence, one might float for quite a while without being able to reach and grab a wall. Not fun.

Danger to the ISS

Since the ISS will have to function properly for the mice to survive, anything they do to impede the smooth functions of the station will hurt their chances.

  • Waste is going to be an issue. Anyone who has owned rodents (or been to a pet store) has some idea of the amount of excrement produced by a mouse colony. The ISS is a closed system and this waste isn't going anywhere. So imagine floating mouse turds and urine entering the air circulation and lodging in nooks and crannies. This will make the station dirty and dangerous for humans (if we leave and turn the lights out behind us the mice are SOL). This will also be a major burden on filtration systems - possibly too much for the system to handle.
  • Mice are going to go poking about looking for comfy spots (aforementioned copulation is one reason) and in the process will not bother treating the hardware of the ISS with care. Any number of situations could arise in which a mouse chews through the wrong cable/bulkhead/seal/etc. and compromises the integrity of the ISS or some subsystem. Even barring some rodent-caused emergency situation, it's almost a certainty that this gnawing problem will eventually be too large a burden and, as before, if humans have to leave it's bad news for mousestronauts.

The Outlook Is Not Great

It might be possible for a multigenerational mouse colony to develop on the ISS if sustenance were available. However, in terms of human generations it would be a very quickly deteriorating situation in which the mice would render their environment unlivable just by behaving naturally.


Cats could be trained to use a litterbox in space, right?

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    $\begingroup$ With regard to both debris and getting stranded, Spacelab crews quickly learned that anything lost would turn up on the air recirculation intake filter in a day or so. So if you wanted to build something that would actually work, some kind of self-cleaning filter... $\endgroup$ Apr 17, 2019 at 3:18
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    $\begingroup$ Mice (and rats, which I've owned several) like to gnaw on certain kinds of cables and other gummy products and if they're hungry probably even more so. So the danger of them damaging vital parts of ISS would be real. I imagine they might accidentally float in open space are a few times but will learn very quickly not to do that or only with the proper impulse. They are very clever and quick learners. There's probably enough "crawling space" for them behind machineries so I expect them to use these especially since closed spaces feels safer to them. $\endgroup$
    – DarkDust
    Apr 17, 2019 at 7:06
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    $\begingroup$ Training a cat to use a litter box in space ... good luck with that one! ;-) Is there a design/patent for a kitty litter box that would have non-dispensable litter in space? $\endgroup$
    – Fred
    Apr 17, 2019 at 9:42
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    $\begingroup$ Great answer! I've just asked How would a mousetrap for use in space work? $\endgroup$
    – uhoh
    Apr 17, 2019 at 15:21

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