An endangered species is any animal or plant that's at risk of extinction due to a sharp decline in population or the depletion of its critical habitat. 

The United States Endangered Species Act of 1973 (ESA) established criteria to designate a species as either endangered or threatened, and ruled that animals on the endangered species list would be protected under federal law. The ESA also required a recovery plan for species suffering from critical habitat destruction. In the decades since the act was passed, the United States government has significantly weakened the ESA by making it easier to remove endangered animals from the list, decreasing protections for threatened species, and considering economic factors when deciding whether a species deserves protection. 

In 1964, the International Union for Conservation of Nature established the Red List of Threatened Species (or the IUCN Red List), a comprehensive global endangered species list. This list uses scientific criteria to evaluate a species’ risk of extinction and develop conservation efforts to protect the thousands of endangered species and subspecies around the world.

There are five primary reasons that a wild animal species might become endangered.

1. __Habitat loss__: In some cases habitat loss occurs naturally, but the primary cause of habitat destruction is human activity—including land development for agriculture, housing, and industry.
2. __Climate change and pollution__: Climate change and pollution have dramatically altered the ecosystems where many now-endangered species previously thrived.
3. __Overhunting, overfishing, and poaching__: Populations of animals like elephants, rhinos, and tigers have dramatically shrunk as a result of hunting and poaching.
4. __Invasive species__: A non-native species that's been accidentally or purposely brought to a new ecosystem can wipe out a population of animals that previously thrived in that area.
5. __Disease__: Genetic variation lets a species adapt to environmental changes, but low-population species have less genetic variation because of inbreeding and thus also have less disease resistance.

The IUCN Red List of Threatened Species classifies species into nine groups.

1. __Extinct (EX)__: The species no longer exists.
2. __Extinct in the wild (EW)__: The species exists only in captivity, cultivation, or outside its native range.
3. __Critically endangered (CR)__: The population of the species is critically low.
4. __Endangered (EN)__: There is a high risk of the species’ extinction in the wild.
5. __Vulnerable (VU)__: The species is at high risk of human-caused extinction.
6. __Near threatened (NT)__: The species is close to reaching a high risk of extinction in the near future.
7. __Least concern (LC)__: The species is unlikely to face risk of extinction in the near future.
8. __Data deficient (DD)__: There is insufficient information to properly assess the species' conservation status.
9. __Not evaluated (NE)__: The IUCN has not yet studied a species' conservation status.
In total, 32,000 species are at risk of extinction. All of the species below are notable examples, each categorized as either critically endangered, endangered, or vulnerable on the IUCN Red List of Threatened Species. 

1. __African wild dog__: 1,409 remaining
2. __Amur leopard__: 84 to 100 remaining
3. __Asian elephant__: Fewer than 50,000 remaining
4. __Black-footed ferret__: 370 remaining
5. __Black rhino__: About 5,600 remaining
6. __Blue whale__: 10,000 to 25,000 remaining
7. __Bluefin tuna__: Remaining population unknown
8. __Bonobo__: 10,000 to 50,000 remaining
9. __Chimpanzee__: 172,700 to 299,700 remaining
10. __Eastern lowland gorilla__: Remaining population unknown
11. __Galápagos penguin__: Fewer than 2,000 remaining
12. __Giant otter__: Fewer than 5,000 remaining
13. __Giant panda__: 1,864 remaining
14. __Hawksbill turtle__: Fewer than 25,000 nesting females remaining
15. __Hippopotamus__: 115,000 to 130,000 remaining
16. __Javan rhino__: 72 remaining
17. __Kakapo__: 209 remaining
18. __Leatherback sea turtle__: Between 34,000 and 36,000 nesting females remaining
19. __Mountain gorilla__: More than 1,000 remaining
20. __North Atlantic right whale__: 300 to 350 remaining
21. __Orangutan__: 119,346 remaining
22. __Polar bear__: 22,000 to 31,000 remaining
23. __Red panda__: Fewer than 10,000 remaining
24. __Snow leopard__: 4,080 to 6,590 remaining
25. __Sumatran elephant__: 2,400 to 2,800 remaining
26. __Sumatran rhino__: Fewer than 80 remaining
27. __Tiger__: Around 3,900 remaining (including both subspecies of tiger, *Panthera tigris tigris* and *Panthera tigris sondaica*)
28. __Western lowland gorilla__: Remaining population unknown
29. __Western Steller sea lion__: About 46,000 remaining
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Extinction rates for wild animal species are accelerating faster than ever, due to human activity. As part of their efforts to prevent permanent loss of wildlife species, conservationists keep a categorized endangered species list to track the populations of animals at risk of extinction.


Extinction rates for wild animal species are accelerating faster than ever, due to human activity. As part of their efforts to prevent permanent loss of wildlife species, conservationists keep a categorized endangered species list to track the populations of animals at risk of extinction.


Endangered Species Guide: Why Animals Become Endangered

An endangered species is any animal or plant that&#39;s at risk of extinction due to a sharp decline in population or the depletion of its critical habitat.

What Is an Endangered Species?

The United States Endangered Species Act of 1973 (ESA) established criteria to designate a species as either endangered or threatened, and ruled that animals on the endangered species list would be protected under federal law. The ESA also required a recovery plan for species suffering from critical habitat destruction. In the decades since the act was passed, the United States government has significantly weakened the ESA by making it easier to remove endangered animals from the list, decreasing protections for threatened species, and considering economic factors when deciding whether a species deserves protection.

What Is the Endangered Species Act?

In 1964, the International Union for Conservation of Nature established the Red List of Threatened Species (or the IUCN Red List), a comprehensive global endangered species list. This list uses scientific criteria to evaluate a species’ risk of extinction and develop conservation efforts to protect the thousands of endangered species and subspecies around the world.

What Is the Red List of Threatened Species?

There are five primary reasons that a wild animal species might become endangered.<ol class="mc-m-4"><li class="mc-my-4"> 1. Habitat loss: In some cases habitat loss occurs naturally, but the primary cause of habitat destruction is human activity—including land development for agriculture, housing, and industry. </li><li class="mc-my-4"> 2. Climate change and pollution: Climate change and pollution have dramatically altered the ecosystems where many now-endangered species previously thrived. </li><li class="mc-my-4"> 3. Overhunting, overfishing, and poaching: Populations of animals like elephants, rhinos, and tigers have dramatically shrunk as a result of hunting and poaching. </li><li class="mc-my-4"> 4. Invasive species: A non-native species that&#39;s been accidentally or purposely brought to a new ecosystem can wipe out a population of animals that previously thrived in that area. </li><li class="mc-my-4"> 5. Disease: Genetic variation lets a species adapt to environmental changes, but low-population species have less genetic variation because of inbreeding and thus also have less disease resistance. </li></ol>

5 Reasons Species Become Endangered

The IUCN Red List of Threatened Species classifies species into nine groups.<ol class="mc-m-4"><li class="mc-my-4"> 1. Extinct (EX): The species no longer exists. </li><li class="mc-my-4"> 2. Extinct in the wild (EW): The species exists only in captivity, cultivation, or outside its native range. </li><li class="mc-my-4"> 3. Critically endangered (CR): The population of the species is critically low. </li><li class="mc-my-4"> 4. Endangered (EN): There is a high risk of the species’ extinction in the wild. </li><li class="mc-my-4"> 5. Vulnerable (VU): The species is at high risk of human-caused extinction. </li><li class="mc-my-4"> 6. Near threatened (NT): The species is close to reaching a high risk of extinction in the near future. </li><li class="mc-my-4"> 7. Least concern (LC): The species is unlikely to face risk of extinction in the near future. </li><li class="mc-my-4"> 8. Data deficient (DD): There is insufficient information to properly assess the species&#39; conservation status. </li><li class="mc-my-4"> 9. Not evaluated (NE): The IUCN has not yet studied a species&#39; conservation status. </li></ol>

9 Categories of Endangered Species

In total, 32,000 species are at risk of extinction. All of the species below are notable examples, each categorized as either critically endangered, endangered, or vulnerable on the IUCN Red List of Threatened Species. <ol class="mc-m-4"><li class="mc-my-4"> 1. African wild dog: 1,409 remaining </li><li class="mc-my-4"> 2. Amur leopard: 84 to 100 remaining </li><li class="mc-my-4"> 3. Asian elephant: Fewer than 50,000 remaining </li><li class="mc-my-4"> 4. Black-footed ferret: 370 remaining </li><li class="mc-my-4"> 5. Black rhino: About 5,600 remaining </li><li class="mc-my-4"> 6. Blue whale: 10,000 to 25,000 remaining </li><li class="mc-my-4"> 7. Bluefin tuna: Remaining population unknown </li><li class="mc-my-4"> 8. Bonobo: 10,000 to 50,000 remaining </li><li class="mc-my-4"> 9. Chimpanzee: 172,700 to 299,700 remaining </li><li class="mc-my-4"> 10. Eastern lowland gorilla: Remaining population unknown </li><li class="mc-my-4"> 11. Galápagos penguin: Fewer than 2,000 remaining </li><li class="mc-my-4"> 12. Giant otter: Fewer than 5,000 remaining </li><li class="mc-my-4"> 13. Giant panda: 1,864 remaining </li><li class="mc-my-4"> 14. Hawksbill turtle: Fewer than 25,000 nesting females remaining </li><li class="mc-my-4"> 15. Hippopotamus: 115,000 to 130,000 remaining </li><li class="mc-my-4"> 16. Javan rhino: 72 remaining </li><li class="mc-my-4"> 17. Kakapo: 209 remaining </li><li class="mc-my-4"> 18. Leatherback sea turtle: Between 34,000 and 36,000 nesting females remaining </li><li class="mc-my-4"> 19. Mountain gorilla: More than 1,000 remaining </li><li class="mc-my-4"> 20. North Atlantic right whale: 300 to 350 remaining </li><li class="mc-my-4"> 21. Orangutan: 119,346 remaining </li><li class="mc-my-4"> 22. Polar bear: 22,000 to 31,000 remaining </li><li class="mc-my-4"> 23. Red panda: Fewer than 10,000 remaining </li><li class="mc-my-4"> 24. Snow leopard: 4,080 to 6,590 remaining </li><li class="mc-my-4"> 25. Sumatran elephant: 2,400 to 2,800 remaining </li><li class="mc-my-4"> 26. Sumatran rhino: Fewer than 80 remaining </li><li class="mc-my-4"> 27. Tiger: Around 3,900 remaining (including both subspecies of tiger, Panthera tigris tigris and Panthera tigris sondaica) </li><li class="mc-my-4"> 28. Western lowland gorilla: Remaining population unknown </li><li class="mc-my-4"> 29. Western Steller sea lion: About 46,000 remaining </li></ol>

29 Examples of Endangered Species

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Extinction rates for wild animal species are accelerating faster than ever, due to human activity. As part of their efforts to prevent permanent loss of wildlife species, conservationists keep a categorized endangered species list to track the populations of animals at risk of extinction.