Russian and German scientists revived a bdelloid rotifer frozen in Siberian permafrost for approximately 24,000 years. The multicellular organism resumed normal biological activity and reproduced asexually after researchers thawed it in a laboratory.
The study, published in Current Biology, pushes the known limits of cryptobiosis. This state allows organisms to suspend their metabolism to survive extreme environments that’d otherwise be fatal.
Rotifers possess more complex internal structures, including digestive systems, compared to the single-celled organisms and simple animals that’ve previously demonstrated this level of survival.
These microscopic animals typically measure between 0.1 and 0.5 millimeters in length. They’re often called “wheel animals” since a crown of cilia surrounding their mouths creates a rotating appearance when beating.
Ice-rich loam preserved the organism
Researchers extracted the specimen from the Late Pleistocene Yedoma formation, also known as the Ice Complex, in northeastern Yakutia. The core contained ice-rich loam and well-preserved mammal mummies.
These conditions suggest a syncryogenetic formation where sediment layers froze quickly after they formed and never melted. This environmental stability effectively halted biological time for the rotifer.
Why the revival challenges biological limits
Lead researcher Stas Malavin described the findings as the strongest proof that multicellular animals can withstand tens of thousands of years in a state of almost completely arrested metabolism.
The rotifer’s ability to reproduce asexually indicates its cellular structures remained intact despite millennia in the ice. It didn’t just wake up; it sustained normal biological functions.
This discovery expands the scientific foundation for studying suspended animation. It doesn’t make human cryopreservation a reality, but it provides critical data on how biological materials resist degradation over vast timescales.
What are rotifers?
Rotifers are diverse, microscopic multicellular animals found in aquatic environments, soil, and moss. They feed on algae, bacteria, and organic particles, serving as key links in aquatic food webs.
How did the animal survive for 24,000 years?
The animal survived through cryptobiosis, a state where metabolic processes slow to nearly zero. This allowed the organism to endure the extreme cold of the Siberian permafrost without its cells degrading.
