Earth mice sent by NASA to the International Space Station quickly adapted to spaceflight. The rodents even learned to defy microgravity.
Spaceflight mice sent to the ISS would do all the things that a normal house mouse would do: feeding, grooming, huddling, and interacting with other mice. Throughout the duration of their experimental spaceflight, though, the mice also learned to propel themselves in zero gravity.
These behaviors of spaceflight rodents were detailed in a recent study published by the NASA Ames Research Center.
According to the study, behavioral analysis can reveal how animals acclimate to the space environment, and how change in physical activity, feeding, drinking, circadian shifts, and social interactions may alter other experimental measures.
NASA's behavioral study focused on how mouse physiology responds to the spaceflight environment during extended missions and on similarities in response to astronaut crew.
NASA Rodent Center
In 2014, NASA sent 20 mice to live in the NASA Rodent Habitat for the first deployment of the Rodent Research Mission.
Scientists sent female mice aged 16 and 32 weeks old to space wherein the animals spent a total of 37 days in microgravity — a long-duration mission on the scale of the rodent life span.
Their habitat was a caged enclosure specifically designed for the experiment that probed how space and microgravity affect model organisms whose biology has similarities to human body systems.
Overall, the mice behaved normally and were in excellent health condition at the end of the study.
A video showed that during their second day in orbit, the mice began adapting to microgravity while doing usual activities. The mice were seen using locomotion similar to hindlimbing, and they also used momentum to float to their destination.
Such observations indicate that spaceflight mice readily adapted to the habitat, propelling their bodies freely and actively and utilizing the entire volume of space available to them.
A week after the launch, some mice showed a unique behavior. The younger ones were more physically active than their older counterparts.
As shown in the NASA video, on the 11th day of their space flight, the mice were running and chasing each other inside the habitat. Their movements were almost like floating, indicating weightlessness in space. Their "race-tracking" behavior even evolved into a group activity.
The clip also showed a mouse on the other side rotating itself in a position to eat, while another mouse used its tail to balance and grab food. Another rodent grasped a cup inside the enclosure with its hind paw to balance and self-groom.
"The rodents quickly adapted to their new weightless circumstances, for example by anchoring themselves to the habitat walls with their hindlimbs or tails and stretching out their bodies. This pose was similar to mice on Earth standing up on their back legs to explore their environment," according to April Ronca, a researcher at NASA's Ames Research Center and lead author of the paper.
NASA proved that the Rodent Habitat provides the capability to conduct significant long-duration biological research studies on the ISS.
The study is published in the Scientific Reports journal.