What is a Critically Endangered Species?

Diane Goettel
Diane Goettel

A critically endangered species is a species that still exists in the wild but is listed as being at the highest risk for extinction. The The International Union for the Conservation of Nature and Natural Resources (IUCN) is the organization that assesses risk and decides which animals are considered to be critically endangered. One of the major factors in defining a species as being critically endangered is the rapidity in which it is decreasing. If a species population has decreased by 80 percent or more within three generations, then the IUCN will likely add it to the critically endangered list. This also may be the case if there is a very strong likelihood that the population of the species will decrease by 80 percent or more within three generations.

Several subspecies of tigers are critically endangered due to hunting and habitat loss.
Several subspecies of tigers are critically endangered due to hunting and habitat loss.

In order to understand what it means for a species to be critically endangered, it is important to understand the spectrum of endangerment that is used by the IUCN. The spectrum, which is also sometimes referred to as the IUCN Red List, includes seven categories. The top category, which is called "Least Concern" is reserved for species which that to be in very little danger of extinction. It is followed by a category called "Near Threatened," which is used to describe species that are not currently under the threat of extinction but may be in the near future.

The next three points on the IUCN spectrum are all considered to be under the umbrella of "threatened" species, but the threat varies in its severity. The points in this section of the spectrum include "Vulnerable Species," "Endangered Species," and "Critically Endangered Species." One of the key issues regarding these types of endangered animals is that, on the spectrum of endangerment, they are next to the extinct categories. The two extinct categories, which are on the opposite end of the spectrum from "Near Threatened" and "Least Concern" are "Extinct in the Wild" and "Extinct."

The critically endangered species on the IUCN list include plants as well as animals. There are, for example, various types of lilies that are considered to be critically endangered. Animals that are on the critically endangered species list include the Togo slippery frog, Anderson’s salamander, the Gulf Coast jaguarundi, Przewalski’s horse, and the Hawaiian monk seal to name just a few. There are a number of organizations that work to make the threat of endangerment less serious for certain groups of plants and animals.

Diane Goettel
Diane Goettel

In addition to her work as a freelance writer for wiseGEEK, Diane is the executive editor of Black Lawrence Press, an independent publishing company based in upstate New York. She has also edited several anthologies, the e-newsletter Sapling, and The Adirondack Review. Diane has a B.A. from Sarah Lawrence College and an M.A. from Brooklyn College.

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Discussion Comments


@clintflint - Corals won't go completely extinct because we can grow many of them in captivity, if nothing else. There are a lot of critically endangered animals at the moment who only exist in the wild because of captive breeding programs that have saved them. The kakapo in New Zealand is one example of this. They were down to fewer than 50 individuals at one point.

The giant panda is another example and I believe Przewalski’s horse is another one. It's not a perfect solution, but it's better than nothing.


@pleonasm - It's actually an interesting point, because you could make an argument that the critically endangered species list should include more species like corals.

If a creature is extremely slow growing and the population is declining very fast due to a universal change in their environment, then even if it's still relatively widespread right this second, I would put it on this kind of list. Corals are still relatively abundant compared with other critically endangered species. But most scientists seem to think there is very little hope that they will survive the next few decades without going extinct, because the conditions they live in are changing and it doesn't seem like anything is going to stop it.


It never occurred to me that it doesn't just matter how much of a population is left, but also how quickly it is declining. I guess that makes sense though, because there are quite a few species that are only found on small islands and simply wouldn't have a large population to begin with. So if you went by numbers alone, you wouldn't be able to get a clear picture of what is going on with them.

Although I imagine most critically endangered species these days have such tiny populations that it doesn't really matter how quickly they got there.

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