What Creatures Can Be Revived After 46,000 Years of Suspended Animation?

Many creatures are capable of enduring harsh conditions for extended periods of time, but none can compare to the hardiness of roundworms. A recent study published in the journal PLOS Genetics described how scientists revived prehistoric roundworms that had been in a state of suspended animation for 46,000 years in the Siberian permafrost.

The roundworms, found within a fossilized squirrel burrow near the Kolyma River, were determined to be members of a previously unidentified species, now known as Panagrolaimus kolymaensis. The researchers were able to determine the age of the worms by carbon-dating plant material also found in the permafrost.

So how did these prehistoric roundworms survive for such a prolonged period? The roundworms, also known as nematodes, appear to have achieved this astonishing feat by entering a state of inactivity called “cryptobiosis.” During cryptobiosis, metabolic activity is reduced to an extremely low level while the organism waits for environmental conditions to improve. Therefore, while essentially suspended in time, roundworms can exist in a harsh environment that would otherwise be lethal.

Previously, the longest known instance of nematodes in a state of cryptobiosis had been a period of just 39 years, making these prehistoric roundworms a truly miraculous find.

Though some in the scientific community have questioned whether there could be errors in the age calculations of the nematodes, others have praised the findings, which are especially incredible as nematodes are multicellular organisms. The research could even have implications for how to preserve human cells in the distant future.

Behold, the nematode: