The International Union for Conservation of Nature (IUCN) keeps a “Red List of Threatened Species.”
The International Union for Conservation of Nature (IUCN) keeps a “Red List of Threatened Species.” The Red List defines the severity and specific causes of a species’ threat of extinction. The Red List has seven levels of conservation: least concern, near threatened, vulnerable, endangered, critically endangered, extinct in the wild, and extinct. Each category represents a different threat level.