A pair of roundworms was encased in the Siberian permafrost about the time when the Wooly Mammoth roamed freely. After 46,000 years these worms were defrosted in warm water and began to wiggle. This was an indication that life can be paused almost indefinitely. 
The results were published in “PLOS Genetics”. According to researchers at the Institute of Physiochemical and Biological Problems In Soli Science in Russia, these nematodes (roundworms) were buried approximately 130 feet deep. The findings were verified in Germany where the worms were then shipped. They have a lifespan of a few days and were able to produce new generations while in the lab. The timeframe of when they lived was established by a process called radiocarbon dating. The roundworms were able to achieve cryptobiosis (dormant state) because of a special gene which is also present in contemporary roundworms. The hope is that we may learn to adapt more easily to the extreme effects of climate change and in so doing protect ecosystems from collapsing. Since the permafrost is melting there may yet be many more discoveries of our distant past.
https://journals.plos.org/plosgenetics/article?id=10.1371/journal.pgen.1010798https://www.scientificamerican.com/article/46-000-year-old-worm-possibly-revived-from-siberian-permafrost/