Environment
IUCN Red List Categories Explained
The IUCN Red List classifies species by extinction risk into categories from Extinct to Least Concern. The International Union for Conservation of Nature was founded in 1948 and is headquartered in Gland, Switzerland.
Last reviewed 2026-10-15
Categories, from highest to lowest risk
- Extinct (EX) and Extinct in the Wild (EW).
- Critically Endangered (CR), Endangered (EN) and Vulnerable (VU): together called Threatened.
- Near Threatened (NT) and Least Concern (LC).
- Data Deficient (DD) and Not Evaluated (NE) are outside the risk scale.
Exam tips
Questions often ask for the status of a species in the news. Note the status when a species appears in a daily edition and check the IUCN listing. Status can change when assessments are updated.
Frequently asked questions
Where is IUCN headquartered?
Gland, Switzerland.
Which categories count as Threatened?
Critically Endangered, Endangered and Vulnerable.
What does Data Deficient mean?
There is not enough information to assess the species' extinction risk.