A microscopic multi-celled organism has returned to life after being frozen for 24,000 years in Siberia, according to new research.
Scientists dug up the animal known as a bdelloid rotifer from the Alayeza River in the Russian Arctic.
Once thawed, it was able to reproduce asexually, after spending millennia in a state of frozen animation known as crytobiosis.
Previous research said they could survive frozen for up to 10 years.
But the new study, published in Current Biology on Monday, suggested they could last for thousands of years, if not indefinitely.
"The takeaway is that a multicellular organism can be frozen and stored as such for thousands of years and then return back to life - a dream of many fiction writers," Stas Malavin, of Russia's Institute of Physicochemical and Biological Problems in Soil Science, told the Press Association.
He said more research was needed to see how it achieved the feat. The scientists in the study froze and thawed dozens of the animals in a laboratory to examine the process.
Radiocarbon dating aged the bdelloid rotifer specimen at between 23,960 and 24,485 years old.
Bdelloid rotifers are a class of rotifer found in freshwater environments around the world. The name rotifer comes from the Latin meaning "wheel bearer".
The creatures are known for their ability to withstand extremes. They are one of the Earth's most radioactive-resistant animals, according to the New York Times, which reports they can also withstand low oxygen, starvation, high acidity and years of dehydration.
There are reports of other multi-celled organisms coming back to life after thousands of years, including a nematode worm, as well as some plants and mosses.