Tardigrades, tiny creatures also known as water bears or moss piglets, can survive extreme conditions like high temperatures, intense pressure, radiation, and the vacuum of space thanks to their unique ability to enter a cryptobiosis state, stopping their metabolism.

This ability, along with their cellular structure's capability to repair DNA damage and produce protective proteins, makes them incredibly resilient and a subject of interest for studies in medicine and space exploration. They’re fascinating little creatures.

1. Tardigrade Means ‘Slow Paced’

The name “tardigrade” comes from Latin, meaning “slow step,” reflecting their slow movements. Despite this, they're known for their extraordinary resilience, surviving in environments from the deepest oceans to outer space. This resilience is due to their ability to enter cryptobiosis, reducing their metabolism to endure harsh conditions.

2. Tardigrade Are Tiny

Tardigrades are microscopic, about 0.3 to 0.5 mm long, and live in various habitats worldwide. Despite their size, they are mighty, capable of surviving extreme environments thanks to their unique adaptations.

3. They Can Survive Extreme Temperatures

Tardigrades can endure temperatures as high as 151°C and as low as -200°C by entering a cryptobiosis state, replacing their cellular water with a protective substance to prevent damage.

4. They Have a Very Varied Diet

Tardigrades are omnivores that eat plant cells, animal cells, and bacteria. This diverse diet helps them adapt to various environments and contributes to their resilience.

5. There Are Around 1,300 Different Species of Tardigrades

Scientists have identified about 1,300 tardigrade species, each adapted to survive in specific environments, from freshwater to extreme conditions like hot springs and polar regions.

6. They Can Survive Extreme Pressure

Tardigrades can withstand pressures up to 600 megapascals in their tun state. This is much more than the deepest ocean's pressure.

7. They Can Survive Being Boiled in Alcohol

Tardigrades can survive boiling temperatures and, specifically, being boiled in alcohol by entering a tun state. Their metabolism slows and their bodies are protected by special proteins and sugars.

8. Tardigrades Can Dehydrate up to 99% and Still Survive

In extreme dehydration, tardigrades lose up to 99% of their body water and enter cryptobiosis, stopping their metabolism but surviving through special proteins that replace the water, protecting their cells.

9. Tardigrades Can Reproduce Alone

Tardigrades can reproduce through parthenogenesis, where females produce offspring without male fertilization, ensuring their survival in isolated conditions.

10. Tardigrades Can Survive the Vacuum of Deep Space

Tardigrades can endure the vacuum of space thanks to cryptobiosis, which allows them to survive without water and resist extreme temperatures and radiation. When tardigrades were taken to space, exposed to the vacuum, then returned to Earth, two thirds survived and were successfully rehydrated. About half did perish after rehydration, but all of them managed to reproduce beforehand.

11. They Create a Special Protein to Survive Dehydration

When dehydrated, tardigrades produce intrinsically disordered proteins (IDPs), which allow them to enter cryptobiosis and protect their cells. These proteins have potential applications in biomedicine and space exploration.

12. Their Genes Could Help Produce Drought Tolerant Crops

Tardigrade genes, responsible for their dehydration survival, could be transferred to crops to create drought-resistant plants, increasing sustainability in arid environments.

13. They're Also Called Water Bears or Moss Piglets

Tardigrades are known as water bears due to their bear-like shape and aquatic habitats. And you’ll find them living in moss all over the world, hence “moss piglet”. I’m not sure which cutsie name I like more – but I feel like I’m leaning more toward moss piglet.

14. Tardigrades Have Awesome Legs

With eight legs equipped with claws, tardigrades use their unique appendages to navigate their environments, despite their slow movement. The rearmost pair of legs are attached backwards and the tardigrade uses these two legs to grab hold of things.

15. Tardigrades Have Survived Every Extinction Event

Tardigrades have lived through all of Earth's mass extinction events. They really do have unparalleled resilience and survival mechanisms to have survived all five extinction events, including the one that wiped out 97% of all species.

16. Here Before the Dinosaurs

Tardigrades have existed for 600 million years, predating the dinosaurs. And, although everything else from that time period has since evolved or gone extinct, tardigrades are still here, demonstrating their incredible durability and adaptability throughout Earth's history.

17. Tardigrade Eggs Hatch in 40-90 Days

Depending on environmental conditions, tardigrade eggs take 40 to 90 days to hatch. Given how tiny these critters are, I was surprised by how long the hatching process takes. But, on the other hand, their name does mean “slow-paced”, so I guess it makes sense that even their beginnings are slow.

18. They Are Their Own Phylum

As members of the distinct phylum Tardigrada, tardigrades are unique micro-animals with specific traits separating them from other life forms.

19. They Look like Walking Heads

Tardigrades' body structure makes them appear as if they are walking heads because most of their legs extend from the front part of their bodies, adding to their unique “water bear” appearance. Somewhere along the way, they lost the genetic code that creates a distinct head-body-tail lifeform.

20. They Can Last for Decades Without Food or Water

Tardigrades can survive for decades without food or water by entering a state of cryptobiosis, reducing their metabolic processes and water content to survive harsh conditions.

21. They're Resistant to Radiation

Tardigrades can withstand extreme levels of radiation, up to 1,000 times higher than what would be fatal to humans, thanks to protective proteins that shield and repair their DNA.

22. You Can Find Them Yourself

With a microscope and patience, you can find tardigrades in your local environment by collecting and soaking moss or lichen. I’ve got this one on my list of fun science-y things to do with my kids.

23. They'll Probably Outlive Humanity

Given their ability to survive extreme conditions, tardigrades may outlast humanity. Given that they’ve survived all of the other catastrophic mass extinction events, it’s likely they’ll still be here long after we’ve gone. Maybe they’ll be the last survivors of this planet and bear witness to its end.

Sources: Live Science, Smithsonian, National Geographic

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