Japan’s National Institute of Polar Research said its scientists have succeeded in reviving a tardigrade which had been frozen for more than 30 years after being collected in Antarctica.

Tardigrades, also known as water bears, are tiny water-dwelling “extremophiles,” surviving under hostile environments including extreme temperatures, pressure and even radiation. They are known to enter a stage known as cryptobiosis under some conditions, in which they slow or shutdown metabolic activities for an extended period.

The European Space Agency is known to have sent 3,000 tardigrades into space for 12 days in 2007, making them the first animals to survive exposure to space.

The tardigrades used in the study, which are less than 1 millimeter in length, were found among moss plants collected near Showa Station in Antarctica in November 1983. They were kept frozen at minus 20 degrees Celsius and brought back to Japan. The institute said they were unfrozen in May 2014. The samples were originally collected to study moss, but researchers were able to find two tardigrades and an egg, a spokeswoman at the institute said. They succeeded in reviving the egg and one of the eight-legged animals, which began moving and consuming food after about two weeks. It laid 19 eggs, of which 14 hatched. While the first eggs laid took longer than the later ones to hatch, no anomalies were found among the newborns. The study was published on Cryobiology magazine last month. Tardigrades had previously been revived after nine years but none as long as 30 years, according to the institute. "Further more detailed studies will improve understanding of mechanisms and conditions underlying the long-term survival of cryptobiotic organisms," the researchers said in their study.

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