Animal brought back to life after spending 24,000 years frozen in permafrost

A microscopic creature has been revived after spending 24,000 years buried in Siberian permafrost.

The tiny animal, called a bdelloid rotifer, is known for being tough – capable of surviving drying, freezing, starvation, and low oxygen.

But being able to survive indefinitely, in a state of suspended animation, for more than 20,000 years beneath a frozen landscape is pretty jaw-dropping, even for the most learned biologists.

Previous research suggested rotifers could survive for up to 10 years when frozen, but scientists in a new study used radiocarbon dating to determine that the rotifers they recovered from the permafrost were around 24,000-years-old.

Researchers found the tiny organism in a core of frozen soil extracted from the Alayeza River in the Russian Arctic, after which they allowed it to thaw.

Hailing his team’s findings, Stas Malavin, of Russia’s Institute of Physicochemical and Biological Problems in Soil Science, said: “The takeaway is that a multicellular organism can be frozen and stored as such for thousands of years and then return back to life – a dream of many fiction writers.

“Of course, the more complex the organism, the trickier it is to preserve it alive frozen and, for mammals, it’s not currently possible.

“Yet, moving from a single-celled organism to an organism with a gut and brain, though microscopic, is a big step forward.”

The remarkable creatures seem to be able to survive indefinitelyPA

To follow the process of freezing and recovery of the ancient rotifer, the researchers froze and thawed dozens of them in the lab.

The study, published in Current Biology, found the animals could withstand the formation of ice crystals that happens during slow freezing.

This suggested they had some mechanism to shield their cells and organs from harm at exceedingly low temperatures.

Once thawed, the creature, which belongs to the genus Adineta, was able to reproduce asexually in a process known as parthenogenesis.

Malavin said: “Our report is the hardest proof as of today that multicellular animals could withstand tens of thousands of years in cryptobiosis, the state of almost completely arrested metabolism.”

However, he added that they had not yet identified what exactly had enabled the animals to survive under the ice for even a few years, nor whether the leap to thousands made much difference.

He said more studies were needed and researchers would continue to analyse samples in search of other organisms capable of such long-term cryptobiosis.

The Soil Cryology Lab at Russia’s Institute of Physicochemical and Biological Problems in Soil Science specialises in isolating microscopic organisms from the ancient permafrost in Siberia.

To collect samples, they use a drilling rig in some of the most remote Arctic locations.