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.
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.