Click here for the Red List Categories and Criteria.

Click here for a one page overview of the Red List Categories and Criteria.

The IUCN Red List Categories and Criteria are used widely as an objective and authoritative system for assessing the global risk of extinction for species. They have undergone an extensive review since their first use and the currently used system, IUCN Red List Categories and Criteria version 3.1., were adopted by IUCN Council in February 2000. Under this system, information on geographic range, life-history, population trend, size and structure, threats and conservation measures, is used to evaluate each species against the IUCN Red List criteria and assign it to one of eight Red List categories.

Structure of the Red List Categories and the five Red List Criteria (click image to enlarge) From: Vié, J.-C., Hilton-Taylor, C., Pollock, C., Ragle, J., Smart, J., Stuart, S.N. and Tong, R. 2008. The IUCN Red List: a key conservation tool. In: J.-C. Vié, C. Hilton-Taylor and S.N. Stuart (eds). The 2008 Review of The IUCN Red List of Threatened Species. IUCN Gland, Switzerland.

Red List Categories
There are three threatened categories: Critically Endangered, Endangered and Vulnerable. Species that do not meet the threshold for a threatened category, but are close to qualifying or are likely to qualify for a threatened category in the near future are placed into the Near Threatened category. Species that have been evaluated against the Red List criteria and do not qualify for either a threatened category or Near Threatened are assessed as Least Concern. A species is Data Deficient when there is inadequate information to make a direct or indirect assessment of its risk of extinction using the Red List criteria. The category ‘Not Evaluated’ indicates that a species has not yet been evaluated against the criteria. See the IUCN Red List Categories and Criteria for further information.