Père David's deer (listed extinct in the wild since 2008. However, reintroduction from captive populations began in 1985, with 53 wild herds of varying sizes being recorded in 2003)
Scimitar oryx (listed extinct in the wild since 2000. A herd of 21 was successfully released into the wild in Chad in 2016, producing the first offspring born in the wild in over 20 years in 2017)
Wyoming toad (listed extinct in the wild since 1991, although 853 have been released into the wild since 1995, leading to a population of around 1,500 in 2017)
The Pinta Island tortoise (Geochelone nigra abingdoni) had only one living individual, named Lonesome George, until his death in June 2012. The tortoise was believed to be extinct in the mid-20th century, until Hungarian malacologist József Vágvölgyi spotted Lonesome George on the Galapagos island of Pinta on 1 December 1971. Since then, Lonesome George has been a powerful symbol for conservation efforts in general and for the Galapagos Islands in particular. With his death on 24 June 2012, the subspecies is again believed to be extinct. With the discovery of 17 hybrid Pinta tortoises located at nearby Wolf Volcano a plan has been made to attempt to breed the subspecies back into a pure state.
Not all EW species are rare. An example is the Brugmansia family, where all seven species are widely cultivated but none are found in the wild. Ultimately, the purpose of preserving biodiversity is to maintain ecological function so when a species exists only in captivity, it is ecologically extinct.
Reintroduction is the deliberate release of individuals into the wild, from captivity or from other areas where the species survives. However, it may be difficult to reintroduce EW species into the wild, even if their natural habitats were restored, because survival techniques, which are often passed from parents to offspring during parenting, may have been lost.
An example of a successful reintroduction of a formerly EW species is Przewalski's horse, which as of 2018 is considered to be an endangered species, following reintroduction started in the 1990s.
^"Wyoming Toads Begin To Recover As States Seek Endangered Species Act Overhaul". NPR.
^Gardner, Simon (6 February 2001). "Lonesome George faces own Galapagos tortoise curse". Archived from the original on 4 June 2011.
^Nicholls, H. (2006). Lonesome George: The Life and Loves of a Conservation Icon. London, England: Macmillan Science. ISBN 1-4039-4576-4. Archived from the original on 14 September 2011. Retrieved 28 April 2011.
^"Last Pinta giant tortoise Lonesome George dies". BBC News. 24 June 2012. Retrieved 25 June 2012.
^"Scientists: Extinct Galapagos tortoise species could be resurrected". CTV News. 22 November 2012. Retrieved 25 November 2012.
^Petruzzello, Melissa. "Extinct in the Wild but Still Around: 5 Plants and Animals Kept Alive by Humans". ENCYCLOPÆDIA BRITANNICA. ENCYCLOPÆDIA BRITANNICA. Retrieved 16 November 2019.
^"An extraordinary return from the brink of extinction for worlds last wild horse". 19 December 2005. Archived from the original on 12 February 2012. Retrieved 5 March 2018.