Tardigrades are distinguished by exceptional resistance capacities when they enter life slowed down, or cryptobiosis. They are then able to resist:

• a temperature close to absolute zero and a maximum temperature of 151 °
• very long periods of freezing (tardigrades collected in ice cores and which had been there for 2,000 years have come back to life)
• the void a pressure of 600 megapascals (ie the pressure that would reign at the bottom of a hypothetical ocean 60,000 meters deep)
• an X-ray dose of 570,000 rads (while 500 rads is the lethal dose for humans
• a spacewalk.