A population, species or more inclusive taxonomic group has gone extinct when all its individuals have died. A species may go extinct locally (population extinction), regionally ( extinction of all populations in a country, continent or ocean) or globally. Populations or species reduced to such low numbers that they are no longer of economic or functional importance may be said to have gone economically or functionally extinct, respectively. Species extinctions are typically not documented immediately: for example, the IUCN Red List categories and criteria require there to be no reasonable doubt that all individuals have died, before a species is formally listed as Extinct (see IUCN Red List).