The protozoan commonly known as "water bear" is an extremophile that has engaged many members of the scientific community. The tardigrade is an invertebrate with eight legs and comes in many shapes and sizes. This group has many adaptations such as cryptobiosis which allows it to survive in extreme environments. The tardigrade can be found on land, in water, in sulfur springs and in over 25 species found in the frozen tundra of Antarctica (Miller et al, 2001). To understand these creatures, this article will summarize the taxonomy, reproduction, food, and protective genetics of Tardigrades. The first section of this article will examine how these creatures are divided taxonomically. The "water bear" is a common name for a group of just over 100 genera of protozoa grouped under the Phylum Tardigrada and is a relative of the Phylum Arthropoda. The phylum Tardigrada contains more than 1000 species and is grouped into three classes. There are two main classes, Heterotarigrada and Eutardigrada. The last is the Mesotardigrada and contains only one species, discovered in a sulphurous spring in Japan in 1937 and which has not been seen since. “Water bears” are, like most species, separated into groups according to their characteristics and, more recently, by molecular genetic methods. Heterotarigrada are primarily known for their tuft-like hairs on the appendages and their flattened, undivided scales. Eutardigrada are known as "naked tardigrades" because they lack hard scales or have several separate plates. Tardigrades are then divided into orders by comparing groups based on the appearance of cuticles, feeding tube, claws, and other defining characteristics (Michalczyk, 2014). The tardigrade, due to the possibility of its habitat constantly changing,...... middle of paper ......is first made by a biochemical pathway of using lipids and glyoxylation of them. Trehalose allows cells to be reduced to less than two percent of their water content. Trehalose is found in lower plants and protozoa and is comparable to sucrose in higher organisms. The most recent evidence shows that trehalose molecules interact with and stabilize macromolecules and cell membranes during periods of low water. Experiments have shown that cell membranes dried with trehalose once rehydrated resume their normal functions. This is unlike those without trehalose where biological functionality is lost. It is also believed that trehalose could be used in place of bulk water. These protective qualities allow tardigrades to reappear several years after desiccation. In one case, tardigrades were revived from a moss sample more than 120 years old. (Crow, 2014)