An animal awakes after 24,000 years on ice
A microscopic animal renowned for its resilience has been revived after spending 24,000 years frozen in Arctic permafrost, reports The New York Times. Bdelloid rotifers are complex multicellular invertebrates: Despite being only a few dozen microns wide, they have brains, guts, muscles, and reproductive systems. And they are extraordinarily tough, able to survive high levels of radiation, acidity, starvation, oxygen deprivation, and years of dehydration. Russian scientists found the rotifers in an ice sample they had drilled out of the Siberian permafrost; the wormlike creatures came from a depth of 11 feet, where the temperature stays about 14 degrees Fahrenheit. Back in the lab, the rotifers soon awoke from their hibernation and were even capable of reproducing. Radiocarbon dating confirmed their ancient age. “We revived animals that saw woolly mammoths,” says co-author Stas Malavin. “Which is quite impressive.” This isn’t the first time ancient life has been revived from frozen stasis. Stems of 1,000-yearold Antarctic moss have been regrown, and 30,000-year-old nematodes—a kind of simple worm—have been awakened.
But the rotifers are perhaps the strangest creatures to be revived. Despite being limited to asexual reproduction—there are no males—rotifers have diversified over several million years into more than 450 different species. And scientists still have no idea how they can survive on ice so long. “The outcome of this [study],” says Malavin, “is more questions than answers.”