Tardigrade

Tardigrades, also called water bears or moss piglets, are microscopic animals first described in 1773 by the German zoologist Johann August Ephraim Goeze and formally named Tardigrada, meaning slow walkers, in 1776 by the Italian biologist Lazzaro Spallanzani. These eight-legged segmented micro-animals live in environments from mountaintops and deep seas to tropical rainforests and Antarctica, and are among the most resilient known animals, able to withstand extreme temperatures, intense pressure, radiation, dehydration and starvation, and have even survived exposure to outer space. About 1,500 known species make up the phylum Tardigrada, typically about half a millimetre long as adults, with a short plump body and four pairs of legs ending in claws or adhesive pads, and are common enough in mosses and lichens to be readily found under a low-power microscope.