Some squat lobsters have adopted a symbiotic lifestyle and others colonised chemo-synthetic communities in the deep sea. Prior to 2010, 42 species of squat lob-sters were reported to engage in putative partnerships with a variety of macro-invertebrates but most com-monly with soft and black corals. Twenty-one species of Galatheoidea and 23 of Chirostyloidea are reported to establish some form of symbiotic association with other invertebrates. Thirty-three identified species of squat lobsters, most of them members of the Galathe-oidea, are reported from chemo-autotrophic commu-nities in the deep sea. Given the depth at which most squat lobsters occur, the paucity of information on many aspects of their lifestyle, life history, behaviour and ecology is not surprising.