|Average Length||Usually 0.5 mm (0.020 in)|
|Locomotion||Crawling on eight stubby legs|
|Feeding Behavior||Varies by species|
Tardigrades (also known as waterbears or moss piglets) are a phylum of water-dwelling, eight-legged segmented mico-animals. They are extremophiles—organisms that thrive in either a physically or geochemically extreme condition that would be detrimental to most life on Earth. Tardigrades themselves are capable of withstanding temperatures ranging between absolute zero to well above the boiling point of water, pressures up to six times stronger than those found in the deepest of Earth's oceanic trenches, ionizing radiation at doses hundreds of times higher than what would be considered the lethal dose for a Human, and the vacuum of space. Not only this, but they can go without food or water for more than a decade, transforming into a capsule-like form called a tun while drying out to the point where they are less than 3% water; they can then later rehydrate, forage and reproduce.
Generally speaking, tardigrades are roughly 0.5 mm (0.020 in) long when they are fully grown. They are short and plump creatures with four pairs of legs, each with four to eight claws also known as "disks". The animals are prevalent in mosses and lichens and feed on plant cells, algae, and small invertebrates.
Tardigrades form the phylum Tardigrada, part of the superphylum Ecdysozoa. It is an ancient group, with fossils dating from 530 million years ago, in the Cambrian period.