What can bears, tardigrades, and worms teach us about surviving deep space?

By Dr. Chinta SidharthanReviewed by Susha Cheriyedath, M.Sc.Feb 24 2025

From the depths of winter slumber to the vacuum of space, nature holds the key to astronaut survival. Discover how hibernating animals and microscopic extremophiles could revolutionize human space travel.

Perspective: The utility of animal models to inform the next generation of human space exploration. Image Credit: TajdidProtik / Shutterstock

Long-duration space missions pose significant risks to astronauts, including muscle atrophy, bone loss, and radiation exposure. However, animals such as polar bears and even minute organisms invisible to the eye could provide us with key information for surviving the exacting conditions of space. Additionally, small invertebrates like Caenorhabditis elegans and Drosophila melanogaster—which have been used extensively in space experiments—offer unique genetic insights that could shape astronaut health strategies.

A recent study published in the journal NPJ Microgravity explores how animal models—especially hibernators and extremophiles—can help scientists develop strategies to counteract these dangers, bringing us closer to sustainable deep-space travel. The study also highlights the role of advanced artificial intelligence (AI) techniques in monitoring animal behavior in microgravity, providing critical insights into physiological adaptations.

Human Space Exploration Challenges

As humanity prepares for longer space missions, researchers are focusing on how living organisms adapt to extreme environments. Decades of spaceflight have shown that microgravity and radiation severely impact human physiology, leading to weakened muscles, brittle bones, and cognitive challenges.

However, while countermeasures such as exercise and nutrition help, they may not be enough for missions lasting years. Interestingly, some animals naturally withstand extreme conditions—hibernators such as polar bears and rodents preserve muscle strength despite months of inactivity, and tardigrades can survive harsh radiation and vacuum exposure. Similarly, C. elegans has been studied for its ability to survive spaceflight conditions, and Drosophila models have provided crucial insights into neurobehavioral and cardiovascular changes caused by microgravity.

Scientists are investigating these models to uncover biological mechanisms that could be applied to human space travel. However, challenges ranging from adapting findings to human physiology to ensuring ethical research practices need to be addressed. Ethical oversight is particularly stringent, with all animal research requiring approval from institutions such as NASA’s Flight Institutional Animal Care and Use Committee (IACUC) to ensure humane treatment.

This study examines how different animal models provide insights into space-induced health risks and what steps are required in order to translate these findings into practical solutions for future astronauts.

Exploring Animal Physiology for Space Exploration

The researchers analyzed various animal models to understand how biological adaptations can mitigate the adverse effects of spaceflight. They focused on species known for their resilience to extreme conditions, especially hibernators and extremophiles. The study also reviews the historical role of animals in space missions, from early primate and rodent flights to more recent small-animal studies aboard the International Space Station (ISS).

They examined physiological changes in small rodents that naturally enter states of metabolic suppression, reducing energy expenditure while maintaining muscle and bone integrity. These animals were compared to models of induced hibernation to assess whether similar protective effects could be artificially triggered in non-hibernating species. The potential for synthetic hibernation in astronauts—using metabolic control strategies inspired by hibernating animals—is explored as a possible method to minimize muscle atrophy and conserve energy during long-duration space missions.

Another key focus was on extremophiles, such as tardigrades, which can survive vacuum conditions and extreme radiation. The study examined the molecular and genetic mechanisms that enable these organisms to repair deoxyribonucleic acid (DNA) damage—a capability that could be harnessed to protect astronauts from cosmic radiation. Further research into these mechanisms may provide pathways for enhancing DNA repair in humans, reducing radiation-related health risks during interplanetary travel.

The researchers also reviewed historical spaceflight experiments involving rodents and other small mammals, in which behavioral analysis was conducted to assess stress responses, changes in circadian rhythms, and neurological adaptations in microgravity. Rodent spaceflight studies have shown increased anxiety-like behaviors, altered sleep cycles, and social interaction deficits—insights that could help predict and mitigate psychological challenges in astronauts.

Additionally, these studies examined AI-driven monitoring tools to track movement patterns and physiological indicators of stress. Machine learning-based tracking systems, such as SLEAP and DeepLabCut, have enabled precise behavioral analysis of animals in orbit, helping scientists understand microgravity-induced neurological changes.

Furthermore, the study addressed the logistical and ethical challenges of conducting animal research in space. It explored how improved space habitat design and AI-assisted behavioral tracking could enhance experimental accuracy while minimizing harm to test subjects. The findings suggested that refining these methodologies could lead to breakthroughs in developing biomedical countermeasures for astronauts on long-duration space missions.

Insights from Animal Models

Studies on animal models provided critical insights into human health risks in space. Rodent hibernators displayed remarkable resilience to muscle atrophy, maintaining lean mass and bone density despite prolonged inactivity. This suggested that inducing a hibernation-like state in astronauts could help counteract the detrimental effects of microgravity.

Additionally, extremophiles such as tardigrades demonstrated extraordinary resistance to radiation exposure, which is attributed to their unique DNA repair mechanisms. If similar pathways could be activated in humans, it may be possible to enhance cellular resistance to space radiation and reduce long-term health risks. The study highlights how animals like C. elegans and Drosophila melanogaster—with their well-documented genetic modifications—could serve as experimental models for studying radiation damage at the molecular level.

Rodents exposed to microgravity showed increased anxiety-like behaviors, disrupted sleep cycles, and changes in social interactions. However, some behavioral deficits improved upon returning to Earth, suggesting partial reversibility of spaceflight-induced neurological changes. The study also documents an intriguing phenomenon observed in spaceflight mice: the emergence of repetitive circling behavior, which may be linked to vestibular and stress-related adaptations.

Additionally, ethical considerations in space-based animal research, such as approvals from the National Aeronautics and Space Administration (NASA) Flight Institutional Animal Care and Use Committee, were also discussed.

The study highlighted some limitations, including the challenge of translating findings from animal models to human physiology. The researchers also emphasized the need for advanced AI-driven monitoring techniques to reduce the reliance on invasive procedures on animals. Automated monitoring systems could improve experimental precision while reducing stress-related interference in behavioral studies.

Overall, the findings indicated that studying biological adaptations in animals could be instrumental in developing strategies for astronaut health and performance during long-duration spaceflight. Future research will need to integrate genetic insights, behavioral tracking, and AI-driven analyses to fully harness the potential of animal models for space travel.

Conclusions

Understanding how certain animals survive extreme conditions could provide valuable insights for human space exploration. By leveraging the biological traits of hibernators and extremophiles, scientists could develop innovative ways to counteract spaceflight-induced health risks.

Although translating these findings to human applications remains challenging, continued research in this field could be crucial for enabling safe and sustainable crewed missions to Mars and beyond. Advancing experimental techniques, including AI-assisted behavioral analysis and synthetic hibernation studies, may provide the next breakthrough in space medicine.