If there was an Animal Survival Olympics, these microscopic animals would take all three places. The tardigrades, also known as “water bears” measure between 0.5 and 1.2 millimeters and can be found virtually everywhere on the planet.
This is because of a special state they enter which allows them to withstand extreme conditions.
The latest discovery about the tardigrades came after a sample of moss from East Antarctica that was kept at a temperature of -20 degrees Celsius for 30 years has been thawed. The tardigrades in that patch managed to return back to life and to even reproduce successfully!
So what is their secret to their extreme resilience? When exposed to extreme conditions that would otherwise degrade DNA and destroy life as we know it, these tiny water bears enter a state called cryptobiosis (or anabiosis).
In this state, they expel 95% or more of their water and create proteins and sugars which protect their cells while massively reducing or even suspending their metabolism. Finally, they tuck their legs in and create a pill-shaped “tun”.
In an experiment, they were able to survive 10 days in the vacuum of space and when they returned with the satellite on Earth, they reproduced with no problems.
Tardigrades break every survival record that has been set by nature’s creations. There are 1000 known species of tardigrades and they are spread literally throughout the whole globe.
The last example, as we mentioned before, was their survival after being frozen at -20 degrees C for 30 years. The patch of moss they were frozen in was found in East Antarctica and was taken to a lab and stored at -20 °C.
Thirty years later, it was thawed and in the moss sample scientists could see two tardigrades in their “tun” state, which they nicknamed Sleeping Beauty 1 and 2.
Sleeping Beauty(SB) 2 didn’t manage to survive. Although it revived along with SB-1, it died at day 20. The same can’t be said about SB-1. On the contrary, this girl managed to reanimate itself, eat, reproduce, see its hatchlings come to life and even grow!
You can see the table where each progression is shown with days and actions.
What scientists are trying to find out now is the way these animals come back to life from cryptobiosis and the processes that take place on a cellular level that allow these animals to survive such extreme conditions.
“We want to unravel the mechanism for long-term survival by looking into damage to tardigrades’ DNA and their ability to repair it,” Megumu Tsujimoto, a postdoctoral researcher at NIPR, told The Asahi Shimbun.
Could this hardy species be the one that will bring about the next evolutionary cycle after a possible apocalypse on Earth? Nature is full of surprises and it just shows that it’s ready for anything.