The glossary of statistical terms, published by the Organisation for Economic Co-operation and Development (OECD), states: ‘Endangered species are taxa in danger of extinction and whose survival is unlikely if causal factors continue operating. Included are taxa whose numbers have been drastically reduced to a critical level or whose habitats have been so drastically impaired that they are deemed to be in immediate danger of extinction. Also included are those that possibly are already extinct, in so far as they definitely have not been seen in the wild in the past 50 years..’
The glossary of statistical terms, published by the Organisation for Economic Co-operation and Development (OECD), describes the red list of threatened animals as: ‘…a listing of animals threatened with extinction. The 1994 International Union for Conservation of Nature (IUCN) Red List, compiled by the World Conservation Monitoring Centre, includes more than 6,000 animal species known to be at risk.’
See also: Vulnerable species.