Woodlice/Slaters are crustaceans related to shrimps, lobsters and crabs. They are the only crustaceans that have properly invaded land, without the need to return to water in order to breed, although they tend to be restricted to fairly damp places. Woodlice are quite harmless and in fact beneficial in their proper habitat by promoting the breakdown of dead vegetation and organic matter in the soil. They normally live outdoors but shun the light by hiding under stones, logs, loose bark, leaf-litter etc., or in hollow tree-trunks – almost anywhere that is fairly damp. However, they frequently come indoors and may take up residence inside buildings, surviving in any dark, damp places they can find.