Japanese Scientists Resurrect Frozen Animals from Antarctica

Researchers from Japan’s National Institute of Polar Research have successfully brought a tardigrade back to life after it was frozen for more than 30 years, according to a press release.

You can freeze them, burn them, dry them out or even blast them into space, but humble tardigrades can survive it all. However the remaining tardigrade has since managed to reproduce with a third water bear. The team reports that the original moss sample also contained a tardigrade egg, which was also frozen under the same conditions as the adult tardigrades, and it was thawed as well. The sample had been stored at -20 °C for just over three decades.

It took SB-1 a little longer than a week to fully recover, indicating that these creatures do need time to recover after such a lengthy time being frozen.

“We recorded recovery of two individuals and development of a separate egg of the Antarctic tardigrade providing the longest records of survival for tardigrades as animals or eggs”, the team explained. And, in addition to surviving, some tardigrades have been able to produce healthy offspring.

The minute animal had been collected from moss in Antartica in 1983, before being unfrozen in 2014. Cryptobiosis is used by a number of species in response to hostile environmental conditions such as extreme desiccation, freezing, and oxygen deficiency. The microscopic creature, also known as a “water bear” due to its head shape, is one of the most durable creatures on Earth – it is able to withstand freezing, boiling and can be dried to the point of no moisture and still return to equilibrium after being re-exposed to normal living conditions.

Long-term survival has been one of the most studied of the extraordinary physiological characteristics of cryptobiosis in micrometazoans such as nematodes, tardigrades and rotifers.

Even though the scientists have been able to accomplish a task that appeared impossible, they admit the ability of the tardigrades to survive being frozen for decades still remains a mystery. The researchers feel that continued study of the creatures and their habits will enhance the understanding and overall long-term survival of all cryptobiotic organisms, the recently published study said.

On the first day after rehydration, the surviving tardigrade, affectionately called SB-1, was observed “moving the fourth legs”, and by the sixth day it was “struggling to lift itself”. While the researchers said that the first eggs took a bit longer than later ones to hatch, they found no anomalies amongst the newborn water bears. That record is now held by a nematode worm that managed almost 39 years.