Nematodes frozen in Siberian permafrost during the Pleistocene era 42,000 years ago have been brought back to life. Despite being frozen for tens of thousands of years, two species of these worms were successfully revived, scientists recently reported in a new study. Their findings, published in the May 2018 issue of the journal Doklady Biological Sciences, represent the first evidence of multicellular organisms returning to life after a long-term slumber in Arctic permafrost, the researchers wrote. After defrosting the worms --all female-- the researchers saw them moving and eating, making this the first evidence of "natural cryopreservation" of multicellular animals, according to the study.