Tardigrades, also known as water bears, are a diverse group of charismatic microscopic invertebrates that are best known for their ability to survive extreme conditions. A famous example was a 2007 trip to space where tardigrades were exposed to the space vacuum and harmful ionizing solar radiation, and still managed to survive and reproduce after returning to Earth. Tardigrades are found in all the continents of the world and in different environments including marine, freshwater, and terrestrial.

Tardigrades have survived all five Phanerozoic Great Mass Extinction events,...