Extinct in the wild describes a species, subspecies or isolated population that no longer exists in its historic, natural habitat and survives only in captivity, cultivation programs or managed environments outside its historic range.
In true extinction, there are no living individuals or viable genetic remnants (such as dormant seeds or spores) of the species remaining anywhere. In contrast, extinction in the wild preserves the possibility that, under the right conditions, the species could eventually be returned to functioning ecosystems.
The idea of reversing extinction in the wild is both a technical challenge and an ethical test. Reintroduction requires healthy captive or ex-situ populations, adequate habitat and sufficient ecological niches to support the species without harming existing communities. It demands that the broader ecosystem is sufficiently resilient, and that threats such as habitat destruction, disease and climate pressures have been addressed, so that the organism can become self-sustaining again.
Another important obstacle is frequently a lack of genetic diversity because extinct-in-the-wild species usually start from only a tiny number of surviving individuals. This makes them highly vulnerable to disease and inbreeding depression during breeding programs and after release back into the wild.
The process often begins with habitat restoration, then careful breeding and quarantine protocols, followed by phased releases and long-term monitoring. Success hinges on the species' ability to adapt to a changed world and on ongoing protection from the threats that drove it to near extinction.
The IUCN Red List (Version 2025.2) lists 83 species, subspecies and varieties as extinct in the wild, consisting of 36 animals and 47 plants and fungi. The total number of species tracked in this category changes over time because of the effects of human activity (such as habitat destruction, invasive species and climate change) and because of expanded scientific assessments, including taxonomic updates and the discovery of species that have not existed outside of botanical gardens or specialized collections for decades.
An example of an extinct-in-the-wild organism is the Kihansi spray toad, which lost its highly specific wetland habitat in Tanzania after a river dam altered the local mist ecosystem, but has been successfully bred in U.S. zoos. Similarly, the Hawaiian crow (alala) disappeared from its native forests due to invasive predators and diseases but has been kept alive via intensive conservation breeding. However, pioneering pilot releases on Maui have recently reintroduced small, monitored flocks back into protected wild canopies.
Perhaps the most famous success is Przewalski's horse, which became completely extinct in the wild by the late 1960s due largely to habitat loss, excessive hunting, severe weather events, interbreeding with domestic horses and disease. It was successfully bred in captivity from about 12 to 14 individuals and reintroduced to Mongolia beginning in 1992. Its total wild population has rebounded to between 1,500 to 2,000 individuals and it is now downlisted to endangered species status.
The Toromiro tree vanished from Easter Island due to overexploitation and livestock grazing, but survives in botanical gardens globally. Wood's cycad from South Africa is unique because only a single male specimen was ever found in the wild, and all living specimens are clones cultivated in botanical gardens. Thus it can never reproduce sexually or recover on its own without hybridization or future genetic technology; that is, it is functionally a dead-end in terms of true wild restoration.
Only a tiny fraction of species classified as extinct in the wild have ever been restored to a self-sustaining wild status as a result of intensive, decades-long conservation efforts. One example is the Arabian oryx, which had completely vanished from its desert habitat by 1972 due to hunting. Captive breeding of this antelope in zoos allowed for a series of successful protected releases across the Arabian Peninsula, and in 2011 it became the first species ever downlisted from extinct in the wild to vulnerable on the IUCN Red List.
The Guam rail was completely wiped out by the invasive brown tree snake on Guam in the late 1980s. Conservationists bred this flightless bird in captivity and reintroduced it to Cocos Island and other snake-free islands nearby. In 2019, it became only the second bird in history to bounce back from extinct-in-the-wild status and is currently listed as critically endangered.