Rotifers are among the toughest animals in the world, Malavin told Insider in an email, known for their resistance to extreme environments. They are among the most radiation-resistant animals on Earth, and can endure extreme dehydration and low oxygen.
“If true, this would be an incredible result and extend the recorded ability of Bdelloid rotifers to survive freezing from 10 years to 30,000 years,” Timothy Barraclough, a Professor of Evolutionary Biology who works on rotifers from the University of Oxford, told Insider.
However, he warned that it possible that the animals colonized the ice later than 24,000 years ago, or after the ice core was removed from the ground.
Understanding the biological mechanisms that drove the rotifers to survive such long periods of freezing could help scientists figure out how to better freeze tissues, such as human organs, a press release accompanying the study said.
“The takeaway is that 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,” Malavin said.
Alexei Savvin stumbled upon an unprecedented find walking near the Tirekhtyakh River in Yakutia, Siberia last August: an almost perfectly-preserved woolly rhino carcass.
Most of the rhino’s hooves, teeth, and internal organs were still intact. The animal still had some of its thick, fur coat, and researchers even found its horn, which had broken off but lay nearby.
After analyzing the carcass, Siberian scientists announced on Tuesday that the rhino likely lived between 20,000 and 50,000 years ago.
It is one of the most intact ancient rhinos ever found.
“The young rhino was between three and four years old and lived separately from its mother when it died, most likely by drowning,” Valery Plotnikov, a paleontologist from the Russian Academy of Sciences, told the Siberian Times.
“The rhino has a very thick short underfur, very likely it died in summer,” Plotnikov added.
The rhino used its horn to forage for food
Siberian scientists hope to take the carcass to a laboratory for radiocarbon dating next month in order to get a better sense of how many thousands of years ago the animal died. There, they aim to also discover what gender the rhino was.
For now, they’re waiting for roads to open up between where Savvin found the rhino and the nearby city of Yakutsk.
According to Plotnikov, finding the rhino’s small horn was a stroke of luck.
Woolly rhinos lived throughout Europe and northern Asia until they went extinct about 14,000 years ago near the end of the last Ice Age. The creatures had two horns – one small horn between its eyes and another large one that protruded upward – and were covered in a thick, fur coat.
These herbivores munched on grasses; adults could reach lengths of 13 feet and weigh up to 2.2 tons (4,400 pounds).
Not the first find of its kind
Discoveries like this one are likely to become more common as Earth’s temperatures continue to rise.
As the planet warms, the permafrost – ground in the Northern Hemisphere that remains frozen all year – is beginning to thaw. As it melts, ice-age creatures like this woolly rhino that were entombed for tens of thousands of years are starting to be unearthed.
In 2014, scientists found a baby woolly rhino carcass – nicknamed Sasha – in the same region of Siberia that this new rhino was found.
The baby rhino died at the age of seven months and had two little horns.
Yakutia yielded another find in 2019: scientists discovered a 40,000-year-old severed wolf’s head, complete with fur, teeth, brain, and facial tissue on the banks of a river.
In a similar finding this past September, Siberian researchers announced they’d found a perfectly preserved adult cave bear – with its nose, teeth, and internal organs still intact. Scientists think the bear died 22,000 to 39,500 years ago. Its species, Ursus spelaeus, lived during the last ice age and then went extinct 15,000 years ago.
The Siberian permafrost has also revealed two perfectly preserved extinct cave-lion cubs, as well as an ancient baby horse that died in a mud pit 42,000 years ago. The foal’s hair, skin, tail, and hooves were all intact.