The water bear (or tardigrade, or moss piglet (!)) is a water-dwelling micro-animal (0.020 inches in length) found often in mosses and lichens. It can go without food or water for more than 10 years, and can survive temperatures from around absolute zero to above 100 degrees Celsius, pressures 6 times greater than those found in deep ocean trenches, radiation at doses hundreds of times higher than will kill a human, and the vacuum of space.
Meet the tardigrade—a tiny, nearly indestructible creature, and one of the stars of the upcoming exhibition, Life at the Limits: Stories of Amazing Species, opening 4/4. Typically found near water, tardigrades can survive just about anywhere, from the bottom of the ocean, to a Himalayan mountain, to the surface of a glacier. “They can survive the loss of almost 100% of their water,” said Dr. Mark Siddall, a parasitologist and curator of the upcoming exhibition. Tardigrades even survived when they were blasted into space and left outside in the subzero, oxygen-deprived vacuum for 10 days. Pictured is Paramacrobiotus craterlaki, a carnivorous tardigrade found living in moss at a crater lake in Kenya.
Tardigrades are notable for being one of the most complex of all known polyextremophiles. (An extremophile is an organism that can thrive in a physically or geochemically extreme condition that would be detrimental to most life on Earth.) For example, tardigrades can withstand temperatures from just above absolute zero to well above the boiling point of water, as well as pressures greater than any found in the deepest ocean trenches, along with solar radiation, gamma radiation, ionic radiation— at doses hundreds of times higher than would kill a person and have lived through the vacuum of outer space. They can go without food or water for nearly 120 years, drying out to the point where they are 3% or less water, only to rehydrate, forage, and reproduce.
Usually, tardigrades are 1 millimetre (0.039 in) long when they are fully grown. They are short and plump with 4 pairs of legs, each with 4-8 claws also known as “disks.” The animals are prevalent in moss and lichen and, when collected, may be viewed under a very low-power microscope, making them accessible to the student or amateur scientist as well as the professional.
The tardigrade, better known as a water bear or moss piglet, is a microscopic animal that can be found all over the world. They get their name from the way they move- a rolling gait that resembles the movement of a bear. Water bears are able to survive in environments that would kill any other animal- temperatures as low as -459 F (close to absolute zero) and as high as 304 F, 1,000 times more radiation than other animals, and almost a decade without water. They can even withstand space travel and radiation directly from the sun! They are the ultimate survivors- and are fucking adorable.