Key difference: Endangered and threatened are synonyms. Both mean to face a certain amount of danger. The two terms are often used to refer to species whose existence on our planet is at risk.

Endangered and threatened are two terms that are quite similar in nature. They essentially mean the same thing. Both mean to face a certain amount of danger. If I am at the risk of being attacked, then my life is threatened. However, if I am already threatened, for some time even, then my life is endangered. Endangered essentially means ‘in danger.’ It is usually used when the situation is unchanged for a while; i.e. constant danger.

Dictionary.com defines ‘endangered’ as:

• Threatened with a danger: endangered lives of trapped coal miners.
• Threatened with extinction: The bald eagle may be endangered.

Whereas, ‘threatened’ is defined as:

• To utter a threat against; menace: He threatened the boy with a beating.
• To be a menace or source of danger to: Sickness threatened her peace of mind.
• To offer (a punishment, injury, etc.) by way of a threat: They threatened swift retaliation.
• To give an ominous indication of: The clouds threaten rain.

The two terms are often used to refer to species whose existence on our planet is at risk. The International Union for Conservation of Nature (IUCN) has become dedicated to finding "pragmatic solutions to our most pressing environment and development challenges." The IUCN has issued a Red List, which lists the conservation status of biological species. The categories on the Red List are as follows: Least concern, Threatened and Extinct.

 The IUCN has divided the threatened category into three sub-categories: vulnerable species, endangered species and critically endangered species. Poaching, heavy harvesting, hunting, deforestation and destruction of habitats have been cited as the main reasons for living organisms becoming threatened. The first sub-category is vulnerable, which means that the species still has significant numbers, but the strength of the number has started to decline, creating a cause for concern. The endangered category suggests that number has declined to a significant low and the species may go into extinction in the near future. Under the critically endangered sub-category, the species are almost already extinct, but only exist in certain places.

Threatened species are any species that is facing the danger of being vulnerable to endangerment in the near future. The United States’ Endangered Species Act defines ‘threatened’ as "any species which is likely to become an endangered species within the foreseeable future throughout all or a significant portion of its range.”

Endangered species is a sub-category of the threatened category in the IUCN’s Red list. Endangered species is the population of organisms (animals, plants, birds, etc.) that are facing a high risk of becoming extinct due to their dwindling numbers. Due to the increasing number of species that are falling in this category many countries have issued laws to forbid hunting, restricting land development or creating preserves, in order to tackle this growing problem. When distinguishing a conservation status for animals many factors need to be considered such as statistics such as the number remaining, the overall increase or decrease in the population over time, breeding success rates, known threats, and so on.

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