A tiny water animal from the time of the mammoths has been brought back to life after being buried in permafrost for 24,000 years.
The tiny creature - dug out of the subsurface soil in Siberia in a state of “suspended animation” - has even reproduced, say scientists.
Known as an Arctic rotifer, it measures less than a millimetre - a twenty-fifth of an inch.
Despite its microscopic size, it has a complex body - including a gut and brain.
The breakthrough offers hope of resurrecting prehistoric beasts such as the woolly mammoth and sabre-toothed cat - and even humans.
Discovering the mechanism that protects the cells and organs from disintegration may hold the key to eternal life.
Dr Stas Malavin explained: “The takeaway is a multi-cellular organism can be frozen and stored as such for thousands of years and then return back to life - a dream of many fiction writers.”
The animal, described in the journal Current Biology, belongs to a group of rotifers known as Bdelloids.
It was among a number of specimens collected from the middle reaches of the Alazeya River in Yakutia, northeastern Siberia.
They were more than eleven feet below the surface of the frozen waterway.
Dr Malavin said: “Layers of sediments were frozen relatively quickly after their formation - and have never melted.”
Some of the best and oldest naturally mummified extinct mammals have been unearthed in the area.
They range from prehistoric bisons and ponies - to woolly rhinos and mammoths.
Rotifers live in freshwater pools. Too small to be seen by the naked eye, they eat any bits of plant or meat that can fit in their mouth.
What’s more, they are entirely made up of females. The species has gone without sex for 80 million years.
Reproduction is through a ‘clonal process’ called parthenogenesis in which eggs develop into embryos without fertilisation.
Rotifers are remarkably tough - capable of surviving drying, freezing, starvation and low oxygen.
Now it has been shown they can also persist - for millennia. They are the most advanced lifeform to exhibit immortality.
Dr 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.”
The Soil Cryology Lab in Russia specialises in isolating microscopic organisms from Siberia’s ancient permafrost in Siberia. It remains below freezing point - all year.
To collect samples, his team used a drilling rig in some of the most remote Arctic locations.
Dr Malavin said: “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.”
