What’s more indestructible than a cockroach? Which creature is most likely to outlast all other life on the earth, even after the sun dies? What animal can survive temperatures as low as -458℉, as high as 302℉, and pressures ranging from the vacuum of space to the highest pressures in the deepest sea trenches on earth?
According to a July 14, 2017, report in the journal Scientific Reports, the tardigrade endures these extreme conditions as well as radiation levels hundreds of times higher than the fatal dose for humans.
The tardigrade — also called a water bear, a space bear or a moss piglet — measures about 0.2 inches long, and holds the title of the toughest creature on earth. The tiny water bears live up to 60 years and can survive without food or water for 30. They live in oceans, fresh water, and even on damp moss or lichens all over the world. The tardigrade looks like a chubby caterpillar, with a piercing, tube-like mouth. Moss piglets lumber slowly around their wet environments, sucking the juices of plants and microscopic animals, including other tardigrades.
The Scientific Reports study considered three types of events that could end all life on earth, including asteroids, supernovae, and gamma-ray bursts. Experiencing a large enough asteroid, a close enough supernova or a massive enough gamma ray burst to boil the oceans away and kill tardigrades is highly unlikely, the researchers concluded.
By studying tardigrades on earth, we can guess what types of conditions could support life on other planets. The researchers from Oxford and Harvard universities point out that once life establishes on a planet, complete destruction of living creatures is unlikely.
If the resilient earth tardigrade can resist such harsh conditions, perhaps there is life on Mars or another planet outside our solar system. The water bear gives us encouragement to keep searching!