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The Only Animal That Can Survive in Space Without a Spacesuit

Tardigrade (Water Bear)
Tardigrade (Water Bear). Image by rukanoga via Depositphotos.

When it comes to surviving extreme conditions, one tiny creature reigns supreme. This remarkable organism can withstand temperatures that would freeze or boil most life forms, endure crushing pressures, and even survive the vacuum of space—all without the help of any protective gear or spacesuit. This article delves into the fascinating world of the tardigrade, also known as the “water bear,” and explores the secrets behind its resilience.

Introduction to the Tardigrade

tardigrade
Tardigrade. Image via Depositphotos.

Tardigrades, commonly referred to as water bears due to their plump appearance and lumbering gait, are microscopic organisms belonging to the phylum Tardigrada. First discovered in the late 18th century, these ancient creatures have captivated scientists and nature enthusiasts alike with their extraordinary survival abilities.

The Diversity of Tardigrades

Tardigrade.
SEM image of tardigrade. Image by Schokraie E, CC BY 2.5, https://commons.wikimedia.org/w/index.php?curid=130857154

With over 1,300 known species, tardigrades are incredibly diverse. They inhabit a wide variety of environments, from deep ocean floors to the highest mountain peaks. Despite their minute size—typically ranging from 0.1 to 1.5 millimeters—these hardy organisms have adapted to thrive in virtually every ecosystem on Earth.

Micro-Anatomy Structure and Composition

Tardigrades
Tardigrades. Image by Frank Fox, CC BY-SA 3.0 DE https://creativecommons.org/licenses/by-sa/3.0/de/deed.en, via Wikimedia Commons

Tardigrades have a segmented body covered by a tough cuticle, which is periodically shed and renewed. They possess eight legs, each with tiny claws that aid in anchoring themselves to surfaces. Their simplistic body structure belies a complex internal anatomy, including a complete digestive system and specialized cells designed for surviving extreme conditions.

Astonishing Survival Strategies

Microorganisms and a tardigrade in a soil sample on a farm
Microorganisms and a tardigrade in a soil sample on a farm. Image by wedge via Depositphotos.

Tardigrades excel in surviving conditions that would be lethal to most other life forms. Their secret weapon is cryptobiosis, a reversible state of suspended animation. During cryptobiosis, the water bear expels almost all moisture from its body, significantly reducing its metabolic activity, and forming a protective tun that shields them from environmental extremes.

Enduring the Vacuum of Space

SEM image of Milnesium tardigradum in suspended state (left) and active state (right).
SEM image of Milnesium tardigradum in suspended state (left) and active state (right). Image by Schokraie E, CC BY 2.5, https://commons.wikimedia.org/w/index.php?curid=22716807

In 2007, tardigrades became the first known animal to survive the vacuum and radiation of outer space without protection, onboard the European Space Agency’s FOTON-M3 mission. They proved not only resilient in the face of solar radiation but also capable of resuming normal activities upon returning to Earth-like conditions.

Surviving Extreme Temperatures

tardigrade
Rendering of a tardigrade. Image via Depositphotos.

Tardigrades can endure temperatures as low as -328 degrees Fahrenheit (-200 degrees Celsius) or as high as 300 degrees Fahrenheit (150 degrees Celsius). Their cryptobiotic state allows them to tolerate such extremes by halting cellular processes and protecting vital biochemical structures.

Withstanding Intense Pressure

the toughest creature on earth
Tardigrade. Image via Depositphotos

Whether in the depths of the ocean or the emptiness of space, tardigrades can survive immense pressure. In laboratory settings, they have withstood pressures up to 6,000 times atmospheric pressure—far exceeding those in the deepest ocean trenches.

Reproductive Resilience

the toughest creature on earth
Tardigrade. Image via Depositphotos.

Tardigrades exhibit various reproductive strategies, including both sexual and asexual reproduction (parthenogenesis). This flexibility in reproduction contributes to their survival by allowing populations to recover quickly after adverse conditions subside.

Tardigrades’ Role in Ecological Systems

tardigrade
Tardigrade. Image via Depositphotos.

Despite their size, tardigrades play crucial roles in ecosystems. As part of the detritus-based food web, they help decompose organic material, cycling nutrients back into the environment. Their presence in various habitats indicates robust and sustainable ecosystems.

Potential Applications in Science and Technology

tardigrade
Tardigrade. Image via Depositphotos

The tardigrade’s unique proteins and biochemical adaptations are of interest to scientists seeking to develop new technologies. Research into tardigrades could lead to advances in cryopreservation, space travel, and our understanding of extremophiles.

Challenges in Tardigrade Research

Macrobiotid tardigrade - waterbear at 20x, Oklahoma - Flickr - Thomas Shahan
Thomas Shahan, CC BY 2.0 https://creativecommons.org/licenses/by/2.0, via Wikimedia Commons

Studying these micro-arthropods presents challenges due to their size and resilience. While significant strides have been made in understanding their genetics and biology, much of their adaptive capabilities remain a mystery, sparking continued scientific intrigue and research endeavors.

Future Directions in Tardigrade Research

Collembola from the drainage of a hot spring in Lassen County, California
Darron Birgenheier from Reno, NV, USA, CC BY 2.0 https://creativecommons.org/licenses/by/2.0, via Wikimedia Commons

Ongoing research aims to unravel the genetic basis for their resilience and further explore the potential applications of their biological mechanisms. Advances in genetic and microbiological tools promise deeper insights into these extraordinary creatures.

Conclusion: The Importance of Tardigrades

Tardigrades under the microscope. Autofluorescence
Alexander Klepnev, CC BY 4.0 https://creativecommons.org/licenses/by/4.0, via Wikimedia Commons

Tardigrades embody the epitome of resilience in the natural world. Their ability to survive in seemingly uninhabitable conditions makes them invaluable to scientific research and valuable allies in the quest for life beyond Earth. As our understanding of these remarkable organisms grows, so too do the possibilities for applications that could benefit humanity in diverse fields spanning from astrobiology to biotechnology.