11 animals we lost in the last 50 years

The extinction of animal species is one of the most tragic consequences of human interference in nature. It not only means the irreversible loss of unique living beings, but also the collapse of ecosystems whose stability depends on these species. Estimates suggest that around 500 to 1,000 known animal species have gone extinct in recent decades – but this figure includes only those we have documented. Countless lesser-known or still-undiscovered species may also have disappeared without us ever learning they existed.

The exact number of species that have gone extinct in the last 50 years is difficult to determine. This is also because a species is often only officially classified as “extinct” decades after its last sighting. One example is the slender-billed curlew, which was last reliably observed in 1995 but was only declared extinct in 2024.

This delay is no coincidence: it is meant to ensure that a species truly no longer exists before conservation measures are discontinued. Intensive searches over many years are intended to prevent species from being abandoned too early – something known in conservation as the Romeo error. The term refers to Shakespeare’s tragedy in which Romeo mistakenly believes Juliet is dead and then makes a tragic decision. In nature conservation, it describes the danger of prematurely declaring a species extinct and ending all protection efforts even though it may still exist.

Below are eleven animal species that were most likely exterminated in the last 50 years. They are not only a symbol of the loss of biodiversity, but also a reminder of how crucial habitat protection, the containment of invasive species, and the fight against climate change are for the survival of threatened species.

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1. Round Island burrowing boa

The Round Island burrowing boa (Bolyeria multocarinata) was a snake species endemic to Round Island and the only member of its genus within the family of Round Island boas (Bolyeriidae). Round Island, a small uninhabited island northeast of Mauritius, originally offered diverse habitats with hardwood forests and palm savannas that created ideal conditions for specialized species such as this boa.

From the 19th century onward, however, introduced animals such as goats and rabbits drastically altered the island’s ecology. They ate young palms and other plants, which led not only to habitat destruction but also to severe soil erosion. These changes made the island increasingly uninhabitable for the boa.

As early as 1949, the snake was considered rare. Despite the removal of invasive animals and the establishment of a protected area in the 1980s, these measures came too late for the species. Intensive searches between 1976 and 2001 were unsuccessful, and the last sighting dates to 1975. The IUCN officially declared the species extinct in 1994.

2. Madeira cabbage white butterfly

The Madeiran large white (Pieris brassicae wollastoni) was a butterfly endemic to the Portuguese Atlantic island of Madeira and is considered the first European butterfly exterminated by human impacts.

Its extinction is mainly attributed to habitat loss and introduced species. Settlement expansion and agricultural use destroyed the species’ natural habitats, while fertilizer use damaged vegetation. In addition, the introduced small white (Pieris rapae) and a virus associated with it, as well as the cabbage white parasitoid wasp introduced for pest control (Cotesia glomerata), may have further threatened the species as a parasite.

The Madeira cabbage white was last observed in 1977. Intensive searches in the 1980s and 1990s were unsuccessful. The IUCN currently lists the species as “critically endangered (possibly extinct)”, as a final comprehensive search is still pending. However, due to its small range and the decades-long absence of records, experts assume the species is extinct.

3. Japanese otter

The Japanese otter (Lutra nippon) was a nocturnal otter that once lived in rivers, lakes, and coastal areas of Japan. It fed mainly on fish and invertebrates and played a key role in the balance of its aquatic habitats.

Its extinction is attributed to several factors. Habitat loss from urbanization, agricultural expansion, and river straightening destroyed large parts of its natural environment. At the same time, pollution, for example from industrial wastewater and pesticides, burdened waterways and harmed both the food chain and the otters themselves. The species was also heavily hunted for its fur and for trade. The introduction of invasive fish-eaters further intensified the threat, as they became food competitors and placed additional pressure on an already greatly reduced population.

The last confirmed sighting of a Japanese otter was in 1979 on the island of Shikoku. In 2012, Japan’s Ministry of the Environment officially declared the species extinct.

4. Wolterstorff’s newt

The Wolterstorff’s newt (Cynops wolterstorffi) lived exclusively in and around Dian Lake in China’s Yunnan province. This mountain lake at 1,800 meters above sea level offered ideal conditions for the highly aquatic species, especially in shallow shore zones, nearby ponds, and irrigation ditches.

From the mid-20th century onward, China’s rapid industrialization changed the region drastically. The nearby city of Kunming developed into an industrial center, severely polluting and degrading Dian Lake. Chemical wastewater, soil erosion, and the introduction of non-native fish and frogs made the newt’s habitat uninhabitable.

While the newt was still frequently seen in the 1950s, a targeted search in 1979 was unsuccessful. The species has not been recorded since. In 2004, the IUCN officially declared the species extinct.

5. Saudi gazelle

The Saudi gazelle (Gazella saudiya) was native to the arid desert and semi-desert regions of the Arabian Peninsula. Its range covered sandy and rocky plains with scattered acacias, from Kuwait to Yemen.

The main cause of its extinction was excessive hunting. The availability of firearms and off-road vehicles in the 20th century led to uncontrolled hunting that almost completely wiped out the already rare species. Habitat loss from the expansion of settlement and agricultural areas added further pressure.

The last sightings in the wild date to the 1970s. By 1980, the Saudi gazelle was considered extinct in the wild. Genetic analyses of captive animals later showed that these were not pure Saudi gazelles but hybrids of other gazelle species. Pure individuals have never been found again—neither in the wild nor in captivity. Since 2008, the species has been officially listed as extinct by the IUCN.

6. Cuban ivory-billed woodpecker

The Cuban ivory-billed woodpecker (Campephilus principalis bairdii), possibly a subspecies of the North American ivory-billed woodpecker, was once native to Cuba’s lowland forests. These old forests provided ideal conditions thanks to numerous dead and dying trees that hosted beetle larvae.

Already at the beginning of the 20th century, large-scale clearing of lowland forests for agriculture and timber extraction led to a dramatic loss of habitat. The woodpecker then retreated to remote mountain regions in eastern Cuba. But these refuges, too, were heavily impacted by further logging in the 1950s and 1980s. In addition, targeted hunting—especially during the breeding season—accelerated the decline of an already shrinking population.

The last confirmed sighting of a Cuban ivory-billed woodpecker was in 1987 in the mountains of Ojito de Agua. Although the area was later placed under protection, the species remained undetectable. Intensive searches, most recently in 2010 and 2011, produced no evidence. Despite occasional reports of possible sightings and calls, the Cuban ivory-billed woodpecker is considered extinct today.

7. Maui ʻakepa

The Maui ʻakepa (Loxops ochraceus) was a small songbird found only on the Hawaiian island of Maui. Its habitat was limited to wet rainforests and dry koa forests in the higher elevations of the Haleakalā volcano.

Like many of Hawaii’s bird species, the Maui ʻakepa was heavily threatened by introduced species. Introduced mosquitoes transmitted diseases such as avian malaria and pox, against which native birds had no defenses. In addition, invasive plants such as blackberries displaced native vegetation, leading to food shortages. Introduced animals such as frogs and insects also altered the food web and contributed to the decline.

Already in the early 20th century, the Maui ʻakepa population began to shrink markedly. While it was still occasionally seen in the 1970s, it disappeared in the years that followed. The last confirmed observation dates to 1988 in the Hanawi Nature Reserve. Intensive searches and conservation measures failed. In 2023, the species was ultimately removed from the list of threatened species and officially declared extinct.

8. Golden toad

The golden toad (Incilius periglenes), with its striking bright orange coloration, was restricted to a small area of the Monteverde cloud forest in Costa Rica. Its range covered only a few square kilometers, making it especially vulnerable.

Several factors led to the golden toad’s extinction: the 1986/87 El Niño event triggered extreme drought, causing the toads’ key breeding pools to dry up and reproduction to fail. At the same time, the chytrid fungus (Batrachochytrium dendrobatidis) spread, killing amphibians through skin infections. This combination of climatic and disease-related impacts hit the species particularly hard.

In the early 1980s, the golden toad was still numerous, with thousands of animals during the mating season. But in 1987 the population collapsed dramatically: of 43,500 eggs, only 29 tadpoles survived. By 1989, only a single male remained, which was seen as the last representative of the species. Despite intensive searches, the golden toad has not been recorded since and was officially declared extinct by the IUCN in 2004.

9. Slender-billed curlew

The slender-billed curlew (Numenius tenuirostris) was a migratory bird whose range extended from breeding grounds in the western Palearctic to wintering areas in North Africa and South Asia.

Its extinction is mainly attributed to the loss of wetlands that were essential for breeding and stopovers. Many of these areas were converted into farmland or destroyed by drainage, especially in the wintering regions of North Africa and the Middle East. In addition, hunting and a lack of protection at key stopover sites further pressured the shrinking population. Climate change also contributed through altered conditions along migration routes and reduced food availability.

The last unequivocal sighting of a slender-billed curlew was in 1995 in Morocco. In the years that followed, there were repeated unconfirmed reports of occasional observations, but none were ever backed by evidence. Since no further individuals were found despite intensive searches in the suspected range, the species was officially declared extinct in 2024.

10. Catarina pupfish

The Catarina pupfish (Megupsilon aporus) was a small freshwater fish found only in a single spring in southwestern Nuevo León, Mexico. First described in 1972, it reached a maximum length of about four centimeters and was notable for lacking pelvic fins.

In the early 1990s, its habitat began to dry out due to overuse and water extraction for agricultural purposes. At the same time, invasive species put additional pressure on an already highly endangered population. In 1994, the spring dried up completely, and the Catarina pupfish was declared extinct in the wild. In a rescue attempt, some specimens were kept in aquariums in the late 1980s and early 1990s, but breeding proved extremely difficult and numbers steadily declined.

After the death of the last female in 2013, the species was functionally extinct. A final attempt to hybridize the remaining males with the El Potosi pupfish (Cyprinodon alvarezi) produced offspring, but they did not survive long. With the death of the last male in 2014, the species’ extinction was sealed.

11. Yellow-tipped O’ahu Tree Snail

The tree snail Achatinella apexfulva, once widespread on the Hawaiian island of O’ahu, was not only the first scientifically described snail of Hawaii, but also the first snail species of the archipelago officially considered extinct. Its fate is closely tied to the last known individual, the endling “George”, who became known worldwide as a symbol of biodiversity loss.

The decline of A. apexfulva was the result of habitat loss, introduced species, and intensive shell collecting. Clearing for agriculture and settlements, as well as the spread of invasive plant species, irreversibly changed Oʻahu’s forests. Introduced predators such as the rosy wolf snail (Euglandina rosea) and rats also preyed on native snails. In the 19th century, collecting the colorful shells for traditional jewelry had already decimated populations.

In 1997, the last known specimens were brought together in a breeding program, but all offspring died except for a single animal—George. George lived in a University of Hawaii laboratory until his death in 2019 . Without conspecifics, he could not reproduce, and with his death the species disappeared for good.

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What can we learn from extinction?

These eleven animal species symbolize the countless species we have lost in recent decades. Their disappearance illustrates how destructive human interference in nature can be. Habitat destruction, introduced species, and climate change have severely weakened biodiversity worldwide. Often, species are only discovered when they are already threatened.

But these examples also show that there is hope. Successful conservation programs have proven in the past that it is possible to stabilize populations and protect species from extinction—provided there is the will and the resources for long-term measures. The so-called Romeo error reminds us not to give up on species too quickly as long as there is even the slightest chance of rescue.

Our contribution to conservation

Protecting threatened species and their habitats is a task that concerns all of us. Scientists and conservation organizations cannot stop biodiversity loss on their own. Each individual can contribute: by supporting conservation projects, promoting sustainable ways of living, and using natural resources consciously. Educating people about the importance of biodiversity is also a key step in preventing further losses.

The extinction of these eleven animals is a warning—but also a wake-up call. It is our responsibility to protect the remaining diversity of life and ensure that future generations can experience a world rich in species.