A multicellular microorganism has returned to life after freezing for 24,000 years in the permafrost in the Arctic, and has produced replicas of it in a laboratory in Russia, in what some describe as reviving "zombies."

According to the study published in Current Biology on June 7, this published research constitutes the longest survival case for water rotifers in a frozen state ever, as researchers previously found that they can be frozen at a temperature below -20 degrees Celsius. degrees Celsius, and then revived after 10 years.

Multicellular microorganism came back to life after being frozen for 24,000 years (Lyubov Shmakova-Symex)

Strongest evidence to date

Rotifera, which are microscopic multicellular animals found on bottom or attached to plants in freshwater environments, were extracted by Russian scientists from the permafrost beneath the surface of the Eliza River in the Russian Arctic, by drilling to a depth of 3.5 metres.

When the scientists thawed the samples, the researchers discovered rotifers of the genus Adineta after spending thousands of years in a hibernation state known as cryptogenicity, a non-metabolic state that an organism enters in response to difficult environmental conditions, such as drought, freezing and lack of oxygen.

Once the ice melted, these ancient rotifers of freshwater rotifers began to recover and reproduce asexually through parthenogenesis, and their scientific classification was confirmed by gene sequences obtained from samples with morphological and molecular markers.


"Our report is the strongest evidence to date that multicellular animals can survive tens of thousands of years in hibernation,

" said Stas Malavin, a researcher in the Krolgi Laboratory at the Pushchino Scientific Center for Biology in Russia,

lead author of the study. Metabolism almost completely stopped."

Malavin explained to Live Science that rotifers also have mechanisms to repair DNA damage and protect their cells from harmful molecules called reactive oxygen species.

Back to Life

Permafrost can sustain snapshots of life (and death) for thousands of years, and retain a lifelike appearance thousands of years later.

But some species of plants and animals trapped in ancient permafrost have managed to do something even more surprising: come back to life from a frozen state, which is impressive.

For example, the carcass of a young bird was found in the permafrost of Siberia in 2020, and it was 46,000 years old, but it looked like it "died only a few days ago".

A frozen and mummified cave bear was also found in Siberia in 2020. It dates back to about 39,000 years ago, and it still had a fat black nose and a lot of fur.

And in 2012, scientists described how they regenerated 30,000-year-old plants from seed tissues that had been preserved for 32,000 years in ancient permafrost.

Two years later, researchers revived Antarctic moss that had been surrounded by ice in Antarctica for 1,500 years.

Some simple worms, called nematodes, were also revived from ancient permafrost in two Siberian sites: in one site the rocks were about 32,000 years old, and in the other site they were about 42,000 years old.

The more complex an organism, the more difficult it is to keep it alive frozen (Getty Images)

And the last discovered species was first described in 2005 after it was discovered by chance in dry mud next to Billabong in Australia, and it was revived after spending thousands of years in hibernation, where radiocarbon dating showed that the age of the soil was about 24,000 years.

"Organisms surviving isolated from permafrost likely represent the best models for permafrost research," Malavin said, and said these mechanisms could then be tested in cryopreservation experiments with human cells, tissues and organs.

"The more complex an organism is, the more difficult it is to keep it alive in a frozen state ... and for mammals, this is not currently possible," he added.