How Are Animals Placed on the Endangered Species List?

An endangered species list acts as a guide to communicate conservation problems and the need to reduce species extinctions. The International Union for Conservation of Nature (IUCN) publishes its IUCN Red List of Threatened Species, a comprehensive inventory of at-risk plants and animals.

  1. International Union for Conservation of Nature

    • The IUCN Red List is a standard for species extinction risk that relies on the research of 11,000 experts. The Red List's nine categories include endangered species deemed to face a very high risk of extinction. Listing as an endangered species (EN) involves meeting any of the following criteria: population size reduction, geographic range involving extent of occurrence and occupancy, population size of fewer than 2,500 mature adults, population size fewer than 250 mature individuals, probability of extinction of at 20 percent within 20 years or five generations.

    U.S. Fish &Wildlife Service

    • The U.S. Fish &Wildlife Service (FWS) can list, delist or reclassify species deemed in great need of federal protection. The listing process can include a petition process or candidate assessment process. Factors to include a candidate species include habitat or range, over-utilization of species, disease or predation, regulatory mechanisms or survival factors. The FWS announces a proposal in the Federal Register open to public opinion. The FWS decides to approve, withdraw or revise the proposal.

    Earth's Endangered Creatures

    • Many different governments and agencies compile official lists of species status. The Earth's Endangered Creatures website includes findings of many lists, not one specific official endangered species list.