Within seven to 10 days after launching, younger mice participating in ISS experiments began to engage in a notable and extremely GIF-worthy behavior not seen in their Earth-like brethren -- group circling that looks like they're running around a track.
The scientists don't know exactly whystarted becoming more physically active than their grounded counterparts, but say it could be their way of stimulating the body's balance system, which is mostly absent in microgravity.
While more research is needed to better understand the behavior, stress is less likely the cause, the scientists say, as the space mice were healthy and behaved normally other than their repeat laps. They groomed their fur, for example, and huddled together with other mice by anchoring themselves to their habitat walls with their hind limbs or tails and stretching out their bodies.
Mice and humans share some biological similarities, so it's hoped the experiments in NASA's Rodent Hardware System will offer more insight into the effect of microgravity as we look toward more extended missions to the moon and Mars.
"Behavior is a remarkable representation of the biology of the whole organism," April Ronca, a researcher at NASA's Ames Research Center and lead author of the paper, published online in the journal Scientific Reports, said in a statement. "It informs us about overall health and brain function."
The Novartis Institutes for Biomedical Research and the nonprofit Center for the Advancement of Science in Space collaborated with NASA on the study, which looked at the weightless mice over the course of 37 days.
The Rodent Hardware System will be used in future rodent research, but unlikethese subjects don't get benefits like big-screen TVs.