The purpose of this report is to present the physical characteristics of water bears (Tardigrades). Water bears are large, in comparison to other wastewater organisms, usually about less than a mm. The majority of water bears are terrestrial forms that live in water film that surrounds mosses and

lichens. There are approximately 300-400 species, and the majority of these species are terrestrial, there are a few marine species that live in the

interstitial spaces between sand grains. Water bears are not very good swimmers. They prefer to crawl along and cling to a substrate. Water bears

have the capacity to shed or molt their skin and this is done 3-4 times during their lifetime. Water bears have two needle-like stylets (arrow is pointing at

the stylet within its mouth) that they can protrude from their mouth and use for sucking the juices of plant cells. Some species of water bears suck the

juices of nematodes, rotifers, and other small animals. Common American water bear species include Macrobiotus, Echiniscus, and Hypsibius. The

majority of rotifers, specifically in some freshwater species, are parthenogenetic. Meaning that a male is not necessary for reproduction. One

of the intriguing aspects of water bears is a condition known as cryptobiosis.  Cryptobiosis is the capacity to go into a state of suspended animation.  When harsh environmental conditions occur, such as a drought, a water bear is capable of reducing its body moisture content from 85% down to 3%.

Under these conditions, the water bear can withstand temperature extremes, ionizing radiation and oxygen deficiency. They can remain cryptobiotic for

years.