Animals collected in Antarctica in 1983 and kept frozen in a lab for over 30 years have miraculously come back to life after being thawed and rehydrated, according to an article published in the journal Cryobiology.
The animal in question was a species of tardigrade, an eight-legged micro-animal known for being among the hardiest survivors in the animal kingdom. Although these creatures have been known to survive extreme heat, cold, pressure, radiation, and even the vacuum of space, the ability to reanimate after 30 years of deep freeze sets a new benchmark.
Researchers hope that studying these remarkable survivors can lead to breakthroughs in cryobiology.
"We want to unravel the mechanism for long-term survival by looking into damage to tardigrades’ DNA and their ability to repair it," said Megumu Tsujimoto, a postdoctoral researcher at Tokyo's National Institute of Polar Research, to the Asahi Shimbun.
Tardigrades, which are sometimes referred to as "water bears," don't have much in common with the large, furry mammals that they share their namesake with, except for on one account: both tardigrades and bears are capable of a type of hibernation. But tardigrades take hibernation to a whole different level. They tuck in their heads and legs into a pellet-shaped pill of indestructibility. During this state, called a "tun" state, they can slow their metabolism down to less than 0.01 percent of its normal rate and shed 95 percent or more of their water.
It's been shown that while in tun form, tardigrades can withstand boiling water or absolute zero. The length of time under which they are capable of surviving these conditions remains to be fully tested. It seems they are truly imperishable.
The tardigrades to survive this experiment were affectionately nicknamed Sleeping Beauty 1 (SB-1) and Sleeping Beauty 2 (SB-2). Since collection, they had been kept in consistent -20 degrees Celsius temperatures. During the thawing process, they were placed in culture wells that were supplied with algal food and moisture.
Researchers describe the recovery process in their article in Cryobiology as follows: "SB-1 first showed slight movement in its 4th pair of legs on the first day after rehydration. This progressed to twisting of the body from day 5 along with movement in its 1st and 2nd pairs of legs, but the movements remained slow. After starting to attempt to lift itself on day 6, SB-1 started to slowly crawl on the agar surface of the culture well on day 9, and started to eat the algal food provided the culture plate on day 13."
SB-2 started kicking about the same time as SB-1, but about two weeks in it stopped eating and eventually died. SB-1, on the other hand, thrived. In fact, not only did SB-1 seemingly rise from the dead as good as new, it soon began to produce eggs that successfully hatched into offspring, and those offspring went on to produce offspring of their own.
Researchers aren't sure exactly what set the two tardigrades apart, but it's remarkable enough that they both survived the deep freeze. It's perhaps no surprise that these creatures can be found just about anywhere in the world, from atop the Himalayas to the deep sea, and from the polar regions to the equator.
They might just represent the most perfect life form (in terms of survivability) ever to walk the Earth.