The name Grylloblattodea derives from the Latin ‘gryll' meaning cricket and ‘blatta' meaning cochroach, refering to a blend of physical characteristics from both crickets and cockroaches. Their common names are rock crawlers, ice crawlers or icebugs. Rock crawlers were first described in 1915, and this is the second smallest order of insects, with only 25 species described worldwide, within one family, Grylloblattidae, and five genera. They have been described as 'living fossils', and are found in caves or near ice or snow at high elevations in mountains of Asia and western North America. No grylloblattids have ever been found in the Southern Hemisphere. Most species are active below freezing and usually die above 10 degrees Celsius. Adults are wingless and they have 2.0 to 3.5 cm in length. Rock crawlers undergo simple metamorphosis, and young go through about 8 nymphal instars and take up to 7 years to reach maturity. Adults are usually nocturnal, and they are predaceous or omnivorous, feeding on other insects or dead animal and plant matter, hiding beneath stones during the day. The longevity of adults is of at least one year, and females lay eggs when they are about a year old.