Many people believe that space is the one place where no creature from Earth can survive. This is a false belief. There exists a creature on Earth that has been known to survive the harshness of space. In fact, they are said to be so resilient that it is speculated that these creatures will outlive every other life on earth. Known as “tardigrades,” they have existed on earth since the Cambrian period, 541 million years ago.
Tardigrades are microscopic creatures that have eight limbs. They can be found in a wide range of environments, from the deepest seas to the highest mountains, the coldest regions to the hottest deserts. These creatures are capable of surviving large doses of radiation and intense pressure. In fact, tardigrades can withstand pressures of up to 87,000 pounds per square inch, which is six times what one would experience at the bottom of the sea. Most creatures would die under such pressure.
To test the survival ability of tardigrades, European scientists sent them into outer space for 10 days in 2007. When the rocket returned to Earth, the researchers found that almost 68 percent survived the vacuum of space even without access to any water. The creatures revived after just 30 minutes of rehydration. They were also capable of producing viable embryos.
So, how are these creatures able to survive long periods of time without water? Their bodies undergo a very interesting phenomenon in such situations.
“When their environment dries up, so do they. Tardigrades will enter a state called desiccation, in which they shrivel up — losing all but around 3 percent of their body’s water and slowing their metabolism down to an astonishing 0.01 percent of its normal speed. In this state, the tardigrade just persists, doing nothing, until it’s inundated with water again. When that happens, the creature pops back to life like a re-wetted sponge and continues onward as if nothing had happened,” according to Popular Mechanics.
Scientists believe that the tardigrade’s ability to survive harsh environments comes from their ability to manufacture unique proteins that are capable of locking the fragile cell components into position. This essentially ends up protecting the DNA, proteins, and membranes from being shattered when the creature becomes desiccated.
“We are literally just scratching the surface of the biochemistry, the molecular pathways by which these animals cope with these environments,” Sandra McInnes, a tardigrade researcher with the British Antarctic Survey, said to Live Science. When they live in conditions where enough food and water are available, tardigrades have been observed to have a lifespan of around 2.5 years.
In 2018, a unique species of tardigrade was discovered in Japan. Named Macrobiotus shonaicus, the species sports chunky legs unlike the rest of its brethren. Discovered by Kazuharu Arakawa, a researcher at Tokyo’s Keio University, the creature was found to have an extra fold on the inside surface of its legs.
Their eggs are also different from the usual tardigrades. Spherical in shape and pretty solid, the eggs are pockmarked with protrusions that have a chalice-like appearance, topped with a ring of stringy, flexible filaments. It is believed that the protrusions help the eggs get attached to the surface when they are laid.
Worldwide, there are over 1,000 different species of tardigrades. About 20 new species are discovered every year. Macrobiotus shonaicus is the 168th species to have been found in Japan. First discovered in 1773 by a German zoologist, tardigrades are also known by the name “water bears.”