These tiny, pudgy animals are no longer than one millimeter. Tardigrades, which live in water or in the film of water on plants like lichen or moss, can be found all over the world in some of the most extreme environments, from icy mountains and polar regions to the balmy equator and the depths of the sea.
They have eight legs with claws at the end, a brain and central nervous system, and something sucker-like called a pharynx behind their mouth that can pierce food.
And they could outlive us by 10 billion years, according to a recent study
from Oxford University.
It's because they would be largely unaffected by things that could potentially spell doom for Earth and human life in the future, like asteroids, supernovae or gamma ray bursts. As long as the world's oceans don't boil away, tardigrades will live on.
But even if tardigrades have to go without water, it isn't a sacrifice. They've been through worse and come back to life. And no matter what inquiring scientists put them through in the name of science, tardigrade life finds a way.
"In recent years humans have been pretty mean to them: drying them out slowly and quickly, freezing them solid, autoclaving them, exposing them to the vacuum of space and cosmic rays, irradiating them," said Mark Blaxter, professor at the University of Edinburgh's Institute of Evolutionary Biology. "I am sure someone has put them under extreme pressure, maybe even tried really bad music at high volumes, or biting insults.
"When they are dry, they are not really alive. If 'life' is defined as there being biochemistry going on, then a dried up tardigrade is 'not alive,' as without water there is no biochemistry."
The difference is, tardigrades can be revived, come back to life and reproduce after being fro