And of course, to be officially declared extinct, that is dead and gone as dinosaurs are, a species need to go unspotted anywhere for 50 years.

Anyways, threatened, endangered and extinct are the three words often used to describe species that are dying out or have died out due to their fast changing environment, loss of their natural habitat and, increasingly, over population and encroachment of humans.

Here are media examples:

1. The more general term used by the IUCN (International Union for Conservation of Nature) for species at risk of extinction is threatened species, which also includes the less-at-risk category of vulnerable species together with endangered and critically endangered. IUCN categories include:

Extinct: Last remaining member of the species has died, or is presumed beyond reasonable doubt to have died. Examples: Javan Tiger… Dusky Seaside Sparrow.

Extinct in the wild: captive individuals survive, but there is no free-living, natural population. Examples: Alagoas Curassow, Dromedary.

Critically endangered: faces an extremely high risk of extinction in the immediate future. Examples: Huxley Panda, Mountain Gorilla….

Endangered: faces a very high risk of extinction in the near future. Examples: Dhole, Blue Whale… Giant Panda….

Vulnerable: faces a high risk of extinction in the medium-term. Examples: Cheetah… Polar Bear….

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