What does ‘endangered species’ mean?

At WWF, we talk a lot about ‘endangered species.’ But what, exactly, does it mean for a species to be endangered?

Let’s start with the basics.

A species can be an animal, a tree, a coral, a fungus, an insect, or any number of other life forms on this planet (including humans). Altogether we call this range of life ‘biodiversity.’ 

How many species are out there? The honest answer is that we don’t really know. Estimates track well into the millions—with new species discovered regularly.

But we like to study the species we do know of and figure out how healthy they are. That brings us to the term ‘endangered’ and a critical tool for protecting wildlife and wild places.

How healthy is life on Earth?

Each species is different from the next, so it’s no surprise that overall health and longevity varies from one to another, too. Some, like the brown bear, are not in imminent peril, while others, like the Javan rhino, cling to survival.

The International Union for Conservation of Nature maintains a global roundup of animals, plants, and fungi and tells us whether a given species still exists and the likelihood of that species becoming extinct in the future. This Red List of Threatened Species is a cornerstone for conservation, helping us identify which species need our immediate help and what we can do to protect them.


A species falls into one of eight categories:


Experts perform a rigorous assessment of a given species to categorize it, asking a host of crucial questions. Is the species’ habitat shrinking? If so, how quickly? How many individuals are there? Is that number dropping? How drastically?

They look at what threats the species faces, too, and any actions underway to protect it.

While all these categories are important in evaluating life on Earth, the term ‘endangered’ refers specifically to species listed as Critically Endangered, Endangered, and Vulnerable. Here’s how that boils down:

Critically Endangered:

A species considered to be facing an extremely high risk of extinction in the wild.


A species considered to be facing a very high risk of extinction in the wild.


A species considered to be facing a high risk of extinction in the wild.

So far, more than 96,500 species have been assessed for the Red List and more than 26,500 of those are threatened with extinction. Here's how that breaks down:





Reef Corals:


Sharks and Rays:


Selected Crustaceans:






The IUCN Red List also re-assesses how species are doing over time. If things have improved for a given species—meaning the population has grown due to conservation efforts—then that species will be ‘downlisted’ to a less critical status. For example, the giant panda was downlisted from ‘endangered’ to the lesser status of ‘vulnerable’ in 2016 thanks to dedicated work to protect them. The flip side of this is ‘uplisted,’ an indication that a species population is dropping.

Protecting the most vulnerable wildlife
WWF works to save at-risk wildlife from around the globe. We’re protecting and connecting the habitat of endangered tigers; stopping poaching of the critically endangered black rhino; and fighting back against the illegal trade of ivory from vulnerable African elephants.

Learn more about our work and what you can do to help.
Explore WWF’s Wild Classroom for educational activities on species.