Human activity, disease, and natural disasters are the primary causes of extinction for many wild animal species. While captive breeding is an effective solution for increasing the numbers of rare animals, their reintroduction poses challenges. They fail to develop the adaptive abilities, behavioral patterns, and genetic traits needed to find food, avoid predators, or fight disease. This list includes animals extinct in the wild and bred in captivity. Thanks to the efforts of governments and several conservation organizations, some of these animals have also been reintroduced to their natural habitats.
1. Alagoas Kurassov (Mitu Mitu)
The mitu-mitu is a black, glossy pheasant-like bird that once inhabited the forests of northeastern Brazil. The species has been extinct in the wild since 1977, and as of 2008, only 130 individuals remained in two aviaries.
The Alagoas curasso was first described by the German naturalist Georg Marckgrave in 1648 in its native habitat in the forests of northeastern Brazil, now the states of Pernambuco and Alagoas. Its authenticity was questioned, as not a single specimen was found until 1951. By then, fewer than 60 individuals remained in the forests around São Miguel dos Campos. Although increasing habitat destruction became known in the 1970s, large tracts of forest were cleared for sugarcane cultivation.
This bird became extinct due to deforestation and hunting, with the last specimen being spotted and killed in the wild in the 1980s. Due to a lack of official interest, the birds have been kept and bred in two private professional hatcheries in Brazil, which house a total of 130 individuals. Although a reintroduction plan is underway, there are concerns that the bird will again fall victim to illegal hunting. (source)
2. Guam kingfisher
This kingfisher species, native to Guam, USA, became extinct in the wild after 1986, when brown tree snakes were introduced into its habitat. It is currently in a captive breeding program.
The Guam kingfisher is a strikingly colored bird with an iridescent blue back and cinnamon-colored head. It lives in hollows dug in the softwood of Guam's trees. As of 2017, fewer than 200 individuals were kept in captivity on the mainland United States and in Guam hatcheries. Plans are underway to reintroduce Guam kingfishers to another suitable island and even to their native range, if the area can be secured by eliminating the threat posed by tree snakes. However, such safe new habitats have not yet been identified. (source)
3. Kihansi Spray Toad
This small species of toad, endemic to Tanzania, became extinct in the wild in May 2009 due to habitat loss following the construction of the Kihansi Dam in 1999.
The Kihansi splash flap toad is an insectivorous, viviparous animal that carries its eggs internally and then hatches live, free-swimming young. Previously, this toad was endemic only to a two-hectare area at the foot of the Kihansi River Falls in Udzungwa, in the Eastern Arc Mountains of Tanzania, where temperatures and humidity remained constant.
Before their extinction, their population fluctuated between 17,000 individuals and even lower numbers in 2001 and 2002, then rose again to 20,989 in 2003, before plummeting to just three individuals in January 2004. The construction of the Kihansi Dam in 1999 reduced the amount of water flowing from the falls by 90%, resulting in a significant reduction in spray, especially during dry seasons.
In 2001, in an effort to save this species and return it to the wild, the Bronx and Toledo Zoos began a breeding program with 500 Kihansi sprayer toads taken from their natural habitat. Although their unusual lifestyle and breeding method initially presented challenges, the zoos succeeded in maintaining the population. In August 2010, 100 toads were flown to their native Tanzania for reintroduction. Artificial, gravity-fed sprinklers are now used to maintain humidity. (source)
4. Black soft-shell turtle
Native to the Indian state of Assam and Bangladesh, this turtle is a close relative of the Indian peacock softshell turtle and has been considered extinct in the wild since 2002. The only known population lives in a man-made pond, where it depends on humans for survival.
The black soft-shelled turtle is a freshwater turtle originally native to the lower reaches of the Brahmaputra River. The only known population of this turtle currently lives in an artificial pond near the Bayazid Bastami Shrine in Chittagong. According to a 2014 study, dissolved oxygen levels in the pond were only 2.01 mg/L, while the favorable level is 5 mg/L. In 2004, 408 turtles were discovered in the pond, but human food does not provide sufficient nutrition for them, and the area also lacks suitable nesting sites, making it difficult for the eggs to hatch.
The Indian chapter of the Turtle Survival Alliance (TSA) has been working to improve turtle welfare since 2013, moving some nests to a hatchery and protecting several others within the sanctuary. Since young turtles are often preyed upon by larger turtles and fish, and the pond is already overcrowded, an earthen pond was purchased to improve their chances of survival. TSA hopes to eventually repopulate the wild with captive turtle colonies. (source)
5. Father David's deer
The only herd of this semi-aquatic deer species was kept by Emperor Tongzhi of China in his garden in the late 19th century. During the Boxer Rebellion in 1900, German troops occupied the garden and shot all the deer for food, leading to the extinction of this species in its native China.
The only living member of the genus Elaphurus, this semi-aquatic deer feeds primarily on grass and aquatic plants, spends much time in the water, and is a strong swimmer. Fossil evidence of this deer dates back to the Pleistocene and was discovered in Manchuria. It was first introduced to Western science in 1866 by Armand David (Père David), a French missionary working in China, after whom the species was named. Its unique feature is its branched antlers, which grow and are shed twice a year.
Tongzhi kept the world's only herd of deer at the Nanyuan Royal Hunting Gardens in Nanhaizi, Beijing. Several deer were illegally exported to Europe for breeding and display. After they became extinct in China, Gerbrand Russell, 11th Duke of Bedford, acquired the remaining deer from European zoos and raised a herd at Woburn Abbey. Two herds of Father David's deer were reintroduced to China in 1985 and 1987, and by 2005 the population had increased to 2,000 individuals. However, captive breeding reduces the deer's ability to resist predators, and the deer have not retained parasite-defense skills such as grooming. (source)
6. South China tiger
The South China tiger is a relict population of the "stem" tiger and the most distinctive of all subspecies. No known populations have been discovered in the wild since the 1970s due to low prey density, habitat loss, and other human-related factors.
The South China tiger is the smallest tiger subspecies in mainland Asia, although larger than the Sumatran tiger. In the 1950s, there were an estimated 4,000 individuals in the wild, victims of Mao's pest control campaigns as part of the Great Leap Forward. Uncontrolled hunting and the large-scale migration of urban populations to rural areas also contributed to its extinction. By 1982, the population had declined to 150-200 individuals, and by 1987, only 30-40 remained in the wild.
Save China's Tigers, the Wildlife Research Center of the State Forestry Administration of China, and the China Tiger Foundation of South Africa have joined forces to breed tigers in captivity and release them back into the wild. A private reserve in South Africa's Free State province, equipped with expertise, land, and game, will serve as a rehabilitation training facility to help the tigers regain their hunting instincts. The offspring of these trained tigers will be released into pilot reserves in China. (source)
7. Socorro woodlouse
A crustacean endemic to the thermal waters of Cedillo Springs in New Mexico became extinct in the wild in 1988 after a tree root burst a pipe.
Also known as the Socorro isopod, these crustaceans inhabit the thermal waters of the Cedillo Spring in Socorro County, whose temperatures range from 26°C (79°F) to 33°C (91°F). When the spring was rerouted in 1947 to supply the city of Socorro with drinking water, the isopods began living in an old pipe that supplied water to a horse trough and two small concrete pools. In 1988, a tree root ruptured the pipe, cutting off the water supply to the pools. Captive-bred populations of isopods were bred and reintroduced into eight new concrete pools. (source)
8. Socorro's Dove
The pigeon, endemic to Socorro Island off the west coast of Mexico, is believed to have become extinct in the wild due to feral cats or intensive grazing by sheep on vegetation under trees in the forest.
The Socorro turtle dove, a close relative of the black-crowned and eared doves, was last seen in its natural habitat on Socorro Island, part of the Revillagigedo Islands, in 1972. Besides feral cats and sheep, hunting is believed to have been the cause of its extinction in the wild. Most surviving individuals are now in zoos and other institutions in the United States and Germany. In 1994, Socorro was declared a biosphere reserve, and efforts began to control the population of cats, people, and other animals, with the goal of eventually reintroducing the turtle dove into the wild. (source)
9. Sabre-billed oryx
For thousands of years, the oryx was widespread in North Africa. Its population began to decline due to climate change during the Neolithic era and later due to hunting for its horns.
Also known as the scimitar-horned oryx and Saharan oryx, the scimitar-horned oryx inhabited the Sahara Desert until the Neolithic Subpluvial Period, approximately 7500 to 3500 BC, when the land dried out and became desert. Before its extinction, the oryx inhabited the grasslands of Niger and Chad, as well as the fringes of the Sahara. By the 20th century, the northern population had been almost completely wiped out due to habitat loss and hunting, after which the introduction of horses and firearms to nomadic hunters further reduced its numbers.
European settlement, France's involvement in World War II, and the civil war in Chand in the 1960s led to a decline in the southern population of this species. By 1985, only 500 oryx remained, and by 1988, their population had dwindled to just a few individuals.
However, successful captive breeding programs exist, and as of 2015, there were up to 11,000 oryx on farms in Texas, and up to 4,000 in some Gulf Arab states. A small herd was reintroduced to the Ouadi Rima-Ouadi Ahim Nature Reserve in 2016 after spending some time in an acclimatization enclosure. The reserve covers 78,000 square kilometers, almost the size of Scotland, and is one of the largest protected areas in the world. A second group was introduced to the acclimatization enclosure in 2017. (source)
10. Wyoming Toad
An extremely rare species, the toad became extinct in the wild in 1991 due to its reduced fertility due to the discovery of a bacterium that causes red feet. It currently exists only in captivity at the Mortenson Lake National Wildlife Refuge in Wyoming, USA.
The Wyoming toad, also known as the Baxter's toad, once inhabited ponds, floodplains, shallow lakes, backwaters, and especially the shores of Lake Mortenson, located in the Laramie Basin. The toad was common until the 1950s, but its population declined sharply between 1975 and 1978. By 1980, only 25 individuals remained in the wild. Recent research has shown that this is caused by a bacterial infection that causes reddened legs.
Although captive breeding is a logical solution, scientists have found that captive toads cannot live beyond three years, the age at which amphibian breeding is most effective. In 1993, the Sibylla Wildlife Research Center implemented a more intensive captive breeding program, and in 1997, the Saratoga National Fish Hatchery followed suit.
Both facilities raised tadpoles and juvenile toads, releasing them into Lake Mortenson, Lake George, and a private release site. Over 30 years of collaboration between the state, federal agencies, landowners, the University of Wyoming, and nonprofit organizations, the population has grown to 1,500 toads. (source)