IUCN levels of threatened species

What’s the difference between threatened and endangered?

Threatened species are those that are facing threats to their survival, and may be at risk of extinction. The International Union for Conservation of Nature (IUCN) classifies threatened species into different categories, depending on their relative risk of extinction. The term “endangered” is one of these categories.

Officially, threatened species are those listed as:

critically endangered (CR)

endangered (EN)

vulnerable (VU)


In simple terms, these categories are ranked as follows:

• critically endangered (CR) – a species facing an extremely high risk of extinction in the wild

• endangered (EN) – a species considered to be facing a very high risk of extinction in the wild

• vulnerable (VU) – a species considered to be facing a high risk of extinction in the wild.


For more information on levels of threatened and endangered species and their definitions, visit the IUCN Red List website.
Mountain pygmy possum. / ©: Matthew Pauza
The Mountain pygmy possum is listed as Critically Endangered in the IUCN Red List.
© Matthew Pauza
Common Green Turtle Swimming in Indo Pacific Ocean. / ©: Jürgen Freund / WWF-Canon
The Common Green Turtle is listed as Endangered in the IUCN Red List.
© Jürgen Freund / WWF-Canon
Wandering albatross (Diomedea exulans), Antarctica. 05 Nov 2006 / ©: Wim Van Passel / WWF-Canon
The Wandering Albatross is listed as Vulnerable in the IUCN Red List
© Wim Van Passel / WWF-Canon