More than just being a cool and novel trick, the flying mice in the International Space Station can reveal plenty of interesting knowledge about human physiology in space.
Landmark footage of mice adapting and thriving in zero gravity caught the attention of the world, offering a peek at how mice and potentially astronauts adapt to the entirely new environment of the ISS.
One behavioral quirk of the mice aboard the ISS provides a particularly interesting focus of study for scientists.
Young Mice's Circling Activity
In the study published in the journal Scientific Reports, researchers reported that younger mice that were part of the group sent to space ended up being more physically active than their counterparts back on Earth.
More significantly, these younger mice began to showcase new behavior dubbed as "race-tracking." The activity involves the mice running laps around their cage, which even evolved to become a group activity among the younger mice.
For now, scientists aren't aware why the younger mice engage in this behavior.
One possibility is that the physical exercise is rewarding on its own for the mice, according to a NASA report. Another reason could be that this behavior is how they respond to stress. It could also be that the activity provides stimulation to the body's balance system, which isn't present in microgravity.
Scientists believe stress isn't likely to be the cause, since the mice were otherwise normal in behavior and physical health. However, further research is necessary to confirm their theories.
Data of rodent responses in space is important in understanding the effects of spaceflight in astronauts, not only because it allows them to experiment without endangering human lives, but also because it's a faster method.
"Since rodents develop and age much faster than humans, studying rodent model organisms allows scientists to study diseases that may take years or decades to develop in humans," April Ronca, study lead author from NASA's Ames Research Center, explains to Space.com.
Astronaut Exercises In Space
So, mice run laps around their cage, but do astronauts also engage in physical activity in the ISS?
According to NASA, astronauts exercise for an average of two hours every day when they're in space to prevent bone and muscle loss.
The crew of the ISS use specially designed equipment in the microgravity environment of the station, since regular equipment weighs much lighter in space than it does on Earth.
In 2017, The Verge reports that there are three machines at the ISS to provide astronauts with a complete workout, including a bicycle, a treadmill, and a weightlifting machine called the Advanced Resistive Exercise Device or ARED.
Astronauts can't simply run around the ISS like the mice, so they are strapped into the treadmill with a harness and bungee cords to prevent them from floating away.