extinct

Extinct is a conservation and biological term used to indicate that a species or other taxon has no living individuals anywhere. In common usage it applies to species, but it can also refer to subspecies or larger groups such as genera. The status contrasts with endangered or threatened categories, which describe populations that still survive but are at risk of disappearing.

In practice, extinction is determined when there is no reasonable doubt that the last individual has died, and exhaustive surveys in known and expected habitats have failed to locate any living members. International bodies such as the IUCN maintain formal categories for extinction: EX for globally extinct and EW for extinct in the wild, where only individuals in captivity or cultivation remain. There is also the concept of local extinction, where a species no longer occurs in a particular area but survives elsewhere.

Extinction results from a combination of factors that undermine population viability over time. Major causes include habitat destruction and fragmentation, overexploitation (hunting, fishing, or gathering), the introduction of invasive species, climate change, pollution, and disease. Catastrophic events such as volcanic eruptions or meteor impacts can also drive extinction, especially for small or isolated populations.

Notable examples include the dodo and the passenger pigeon, both driven to extinction in historical times, the woolly mammoth whose populations disappeared thousands of years ago, and the Tasmanian tiger, which vanished in the 20th century. The possibility of delayed or unknown extinction in some taxa underscores the importance of ongoing monitoring and conservation efforts. Modern approaches—habitat protection, captive breeding, legal protections, and restoration initiatives—aim to reduce the risk of future extinctions and preserve biodiversity.