Endangered Animals

Endangered animal categories, definitions, and lists

A-Z Animals follows the International Union for the Conservation of Nature (IUCN)’s nine categories of endangered animal lists. They are:

• Extinct (EX) – Extinct species no longer exist. After exhaustive research, scientists around the world agree that there isn't a single living individual of the species on the planet. Interestingly, 99 percent of all species that ever graced the Earth over the past five billion years have gone extinct. Read more and see an extinct animal list here.
• Extinct in the wild (EW) – Species that only survive in captivity, cultivation, or outside their native range are deemed "extinct in the wild." For example, if only 10 individuals of a rare bird are left, and they all live in zoos or on a single nature preserve, the IUCN would classify the species as extinct in the wild. An extinct in the wild list is pending
• Critically endangered (CR) – Critically endangered species are on the brink of becoming extinct or extinct in the wild but have not yet met the criteria for either category. See a list of critically endangered animals here.
• Endangered (EN) – Endangered species are at a very high risk of becoming extinct in the wild or extinct. For an animal to be added to the category, it must meet specific criteria regarding population or habitat decline, which you can read about on our endangered animal species list.
• Vulnerable (VU) – Vulnerable species meet at least one of the five Red List criteria. They're considered to be at high risk of human-caused extinction if conservationists don't intervene. For the IUCN to add a taxon to the Vulnerable animals list, it must meet specific criteria regarding population or habitat decline. Read more on our vulnerable animals page.
• Near threatened (NT) – A species is considered Near Threatened when it doesn't qualify as Critically Endangered, Endangered, or Vulnerable, but scientists believe it will reach one of those levels in the near future. See our near threatened animal list here.
• Least concern (LC) - Species that fall into the Least Concern category are not presently facing any population or habitat declines. See a least concern animal list.
• Data deficient (DD) - Data deficient species lack enough information to properly categorize into one of the groups above. Read more here.
• Not evaluated (NE) - This species has not been evaluated for an IUCN categorization yet. See a list of not evaluated animals.

What is the International Union for the Conservation of Nature (IUCN)?

The IUCN is the organization that monitors the conservation status and other ecological metrics for the world's plants and animals. Its mission is to promote sustainable use of the Earth's resources.

Founded in 1948, in Fontainebleau, France, as the Union for the Protection of Nature, the IUCN is the oldest global environmental advocacy group. Today, headquartered in Gland, Switzerland, the umbrella organization collaborates with over 1,000 smaller nonprofits, associations, and governments representing 140 countries.

How Many Species Occupy the Earth?

The IUCN monitors the world's species, which raises the question: How many species currently occupy the planet?

In 2016, researchers declared their collective belief that over one trillion species currently occupy the Earth. However, scientists have only observed and described about one-thousandth of one percent of them, or 7 to 10 million.

The typical lifespan of a species is 10 million years. However, some stick around for hundreds of millions of years. For example, jellyfish have lived on Earth for nearly 550 million years!

What is a Taxon?

The IUCN frequently uses the word "taxon." So what is it? A taxon is a group of one or more populations of a species or organism that form a unit.

What is the Red List?

The International Union for the Conservation of Nature is perhaps best known for creating the IUCN Red List of Threatened Species, a detailed accounting of the world's vulnerable and endangered species. The list started in 1964 and details at-risk taxons, for both plants and animals, which are separated into several categories.

How Many Animals are Currently Endangered?

You may be wondering: How many animals are endangered, or what animals are endangered in 2020? For the most recent version of the list, IUCN researchers and scientists evaluated 63,837 species. Of that number, 19,817 are threatened with extinction; 3,947 landed in the Critically Endangered category; 5,766 qualified as Endangered, and over 10,000 species are listed under Vulnerable.

What is the Endangered Species Act?

Passed in 1973, the Endangered Species Act is a federal United States law designed to protect threatened and endangered species that are imperiled because of a "consequence of economic growth and development untempered by adequate concern and conservation." The goal of the act is to prevent extinction and recover species to the point where they no longer need protection.