With 24,000 years frozen in the Siberian permafrost it is undoubtedly the longest surviving case of bdelloid rotifers, thanks to the fact that they paused their metabolism for millennia.
This microscopic creature that is found both in fresh water (ponds, streams …) and in damp ground (moss, lichens, tree bark …) and that can move by swimming or crawling, has proven to be an “evolutionary scandal” for having thrived for millions of years without having sex; persist for at least 24,000 years in Siberian permafrost and then be able to reproduce.
These multicellular invertebrates that they are exclusively female, are recognized for their resistance to radiation and their ability to withstand quite inhospitable environments as occurs with other equally striking creatures such as tardigrades: extreme heartburn, dehydration, starvation, and low oxygen.
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They have existed for at least 50 million years and can also come back to life after tens of thousands of years in freezing, according to a study published in the journal Current Biology, whose findings also show that these robust microanimals can also withstand extreme durations of suspended animation.
For the study, the scientists collected samples by drilling roughly 3.5 meters below the surface of the permafrost in northeast Siberia where radiocarbon dating showed the soil to be around 24,000 years old. They discovered live bdelloid rotifers encased in ancient permafrost, whose average temperature is around -10 ° C.
While simple organisms like bacteria can often survive millennia in permafrost, “this is an animal with a nervous system and a brain and all,” says Stas Malavin of the Pushchino Scientific Center for Biological Research RAS in Russia. Rotifers were not known to last that long.