A waterbear is not a bear, it is a tardigrade. it is microscopic. Tardigrades (Tardigrada), also known as water bears or moss piglets, are a phylum of small invertebrates. They can live for 5 years in dehydrated moss and also have been found on the rovers on Mars.
Strange is this little animal, because of its exceptional and strange morphology and because it closely resembles a bear en miniature. That is the reason why I decided to call it little water bear.
- J.A.E. Goeze (Pastor at St. Blasii, Quedlinburg, Germany), 1773