Bdelloid rotifers are multicellular animals so small you need a microscope to see them. Despite their size, they're known for being tough, capable of surviving through drying, freezing, starvation, ...
Scientists were able to revive a tiny, multicellular animal called a bdelloid rotifer that had been frozen in the Siberian permafrost for 24,000 years, reports Marion Renault for the New York Times.