A comparison of the adaptations made by invertebrates in polar deserts with those of temperate and subtropical deserts. These regions represent some of the most hostile environments on earth, demanding an array of strategies for survival. Polar species are well adapted to the cold and have to cope with arid conditions due to low precipitation and lack of liquid water during the winter. Similarly, temperate desert invertebrates have adapted to dry conditions and are also exposed to low winter temperatures. Terrestrial arthropods maintain their water-balance through behavioural and physiological adaptations. Tardigrades and nematodes are remarkable in their ability to shed all their water before entering a state of anhydrobiosis only to be revived when moisture once again becomes available.