Tardigrade (Hypsibius dujardini) walking through algae under a microscope. - 影片檔

Tardigrades are commonly known as water bears or moss piglets. They are found in practically every habitat on Earth, from hot springs to beneath ice sheets, and are renowned for their toughness. Experiments have shown they can survive being frozen to nearly absolute zero and heated to 150 degrees Celsius. They have survived pressures of more than 6000 atmospheres, and have survived after prolonged exposure to the vacuum and radiation found in space. In unfavourable conditions they can dehydrate to 1% of their normal water content and remain alive in stasis for over a decade. In more normal conditions, they prefer moist environments where they feed on algae and bacteria. This tardigrade is often used as a model organism in biological research, and its genome is being sequenced..