The IUCN Red List Categories and Criteria

IUCN Red List Categories

There are nine categories in the IUCN Red List system, ranging from Least Concern to Extinct:

Least Concern (LC): Species in this category are generally widespread and abundant.

Near Threatened (NT): Species in this category are close to qualifying for, or are likely to qualify for, a threatened category in the near future.

Vulnerable (VU): A taxon is Vulnerable when the best available evidence indicates that it meets any of the criteria for Vulnerable, and is as a result considered to be facing a high risk of extinction in the wild.

Endangered (EN): A taxon is Endangered when the best available evidence indicates that it meets any of the criteria for Endangered, and is as a result considered to be facing a very high risk of extinction in the wild.

Critically Endangered (CR): A taxon is Critically Endangered when the best available evidence indicates that it meets any of the criteria for Critically Endangered and is as a result considered to be facing an extremely high risk of extinction in the wild.

Extinct in the wild (EW): A taxon is Extinct in the Wild when it is known only to survive in cultivation, in captivity or as a naturalized population well outside the past range. No individuals were recorded during exhaustive surveys in known and/or expected habitat throughout its historic range. Surveys were carried out in a manner appropriate to the taxon’s biology.

Extinct (EX): A taxon is Extinct when there is no reasonable doubt that the last individual has died. Again, this is based on exhaustive surveys appropriate to the taxon’s biology and in known and/or expected habitat throughout its historic range having failed to record an individual.

For some species, not enough data is available to assign a Red List Category – or the species has not yet had its Red List status evaluated. In these cases, species are attributed to the Data Deficient (DD) category or Not Evaluated (NE) categories:

Data Deficient (DD): A taxon is Data Deficient when there is inadequate information to make a direct, or indirect, assessment of its risk of extinction based on the Red List criteria. A taxon in this category may be well studied, and its biology well known, but appropriate data on abundance and/or distribution are lacking. This category does not give any information about a taxon’s threat status, but highlights the need for more appropriate data on abundance or population status.

Not Evaluated (NE): A taxon is Not Evaluated when it is has not yet been evaluated against the criteria.

For more detailed information on the IUCN Red List Categories, see the IUCN Red List Categories and Criteria version 3.1. Download PDF (486 KB)