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What is a tardigrade?

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Quick answer

A tardigrade, or 'water bear,' is a microscopic animal famous for surviving conditions that would kill almost anything else — extreme cold, heat, radiation, and even the vacuum of space. It endures by drying out into a near-lifeless state and reviving later.

Key things to understand

  1. A tiny, eight-legged animal under a millimeter long.
  2. It survives freezing, boiling, intense radiation, and space vacuum.
  3. It does so by curling into a dried-out 'tun' state, nearly halting life.
  4. In that state its metabolism almost completely stops.
  5. Add water and it can revive, even years later.

People also ask

How do tardigrades survive extreme conditions?
They dry out into a 'tun' state that nearly stops their metabolism and protects their cells, then revive when water returns.
Can tardigrades survive in space?
Yes — experiments showed some survived direct exposure to the vacuum and radiation of space, then revived back on Earth.
Where do tardigrades live?
Almost everywhere — in moss, soil, freshwater, and oceans, from mountaintops to the deep sea.