A tiny animal called a rotifer has been revived after spending 24,000 years frozen in permafrost. It is the longest a rotifer has been observed to survive in such extreme cold.
While simple organisms like bacteria can often survive millennia in permafrost, “this is an animal with a nervous system and brain and everything”, says Stas Malavin at the Pushchino Scientific Center for Biological Research RAS in Russia. It isn’t quite a record – nematode worms have purportedly been revived from permafrost after 30,000 years – but no rotifer has been known to endure for so long.
Malavin and his team drilled into permafrost near the Alazeya river in north-east Siberia, Russia, in 2015. They found a single rotifer, a worm-like creature less than a quarter of a millimetre long. When the researchers warmed it up and gave it food, it became active. It also reproduced, because it is a bdelloid rotifer that can clone itself without the need for a sexual partner.
“We are quite confident that this is a new species for science,” says Malavin. He and his team sequenced the rotifer’s genome and found it was most similar to a species called Adineta vaga, which is thought to include multiple subspecies that haven’t been properly identified.