The extinction of animal species is one of the most tragic consequences of human interference with nature. It not only means the irreversible loss of unique creatures but also the collapse of ecosystems whose stability depends on these species. Estimates suggest that in recent decades, around 500 to 1,000 documented animal species have gone extinct – yet this number only includes those we have recorded. Countless lesser-known or undiscovered species may have vanished without us ever knowing they existed.
The exact number of species that have gone extinct in the last 50 years is difficult to determine. This is partly because a species is often only officially declared “extinct” decades after its last confirmed sighting. One example is the Slender-billed Curlew, which was last reliably observed in 1995 but wasn’t officially declared extinct until 2024.
This delay is intentional: it ensures that a species truly no longer exists before conservation efforts are discontinued. Years of intensive searches aim to prevent prematurely giving up on a species—a cautionary approach known in conservation as the Romeo Error. Named after Shakespeare’s tragedy, the term refers to the risk of mistakenly assuming a species is extinct and halting protection efforts, even though it might still survive in some remote or unknown habitat.
Here are eleven species that were most likely driven to extinction in the last 50 years. Their disappearance is not only a symbol of the loss of biodiversity but also a stark reminder of how critical it is to protect habitats, control invasive species, and combat climate change to ensure the survival of endangered species.
1. Round Island Burrowing Boa

(© Special Collections of the University of Amsterdam, Public domain, via Wikimedia Commons)
The Round Island burrowing boa (Bolyeria multocarinata) was a species of snake endemic to Round Island, a small, uninhabited island northeast of Mauritius. It was the only known member of its genus within the Bolyeriidae family. Round Island once offered a rich habitat of hardwood forests and palm savannas, providing ideal conditions for highly specialized species like the Round Island burrowing boa.
From the 19th century onward, introduced animals such as goats and rabbits drastically altered the island’s ecology. They fed on young palms and other plants, leading not only to habitat destruction but also to severe soil erosion. These changes rendered the island increasingly uninhabitable for the Round Island burrowing boa.
By 1949, the Round Island burrowing boa was already considered rare. Despite conservation efforts in the 1980s, including the removal of invasive animals and the establishment of a protected area, these actions came too late for the species. Surveys conducted between 1976 and 2001 failed to locate any surviving individuals. The last confirmed sighting was in 1975, and the IUCN officially declared the species extinct in 1994.
2. Madeiran Large White

(© A. E. Holt White, Rashleigh Holt White, Public domain, via Wikimedia Commons)
The Madeiran large white (Pieris brassicae wollastoni) was an endemic butterfly species from the Portuguese Atlantic island of Madeira and is considered the first European butterfly to be driven to extinction due to human activity.
Its extinction is primarily attributed to habitat loss and introduced species. Urban expansion and agricultural development destroyed the butterfly’s natural habitats, while the use of fertilizers damaged its food plants. Additionally, the introduced small white (Pieris rapae) and an associated virus, as well as the white butterfly parasite (Cotesia glomerata), introduced for pest control, may have further endangered the species.
The Madeiran large white was last observed in 1977. Extensive searches during the 1980s and 1990s were unsuccessful. The IUCN currently classifies the species as “critically endangered (possibly extinct)” due to the lack of recent, comprehensive surveys. However, given its limited range and the absence of sightings for decades, most experts believe the species is extinct.
3. Japanese River Otter
The Japanese river otter (Lutra nippon) was a nocturnal otter species that once inhabited rivers, lakes, and coastal areas throughout Japan. It primarily fed on fish and invertebrates, playing a crucial role in maintaining the balance of its aquatic ecosystems.

(© KKPCW, CC BY-SA 4.0, via Wikimedia Commons)
Its extinction can be attributed to several factors. Habitat loss due to urbanization, agricultural expansion, and river modifications destroyed much of its natural environment. Additionally, pollution from industrial waste and pesticides severely degraded water quality, harming both the otters and their food sources. The species also faced intense hunting pressure for its fur and trade value. The introduction of invasive fish predators further exacerbated its decline by increasing competition for food, placing additional stress on the already dwindling population.
The last confirmed sighting of the Japanese river otter occurred in 1979 on the island of Shikoku. In 2012, Japan’s Ministry of the Environment officially declared the species extinct.
4. Yunnan Lake Newt

(© Boulanger, Public domain, via Wikimedia Commons)
The Yunnan Lake newt (Cynops wolterstorffi) was an amphibian species endemic to the Dian Lake and its surrounding areas in Yunnan Province, China. This high-altitude lake, situated at 1,800 meters, provided ideal conditions for the highly aquatic species, particularly in its shallow shores, nearby ponds, and irrigation ditches.
Starting in the mid-20th century, rapid industrialization drastically altered the region. The nearby city of Kunming became an industrial hub, leading to severe pollution and degradation of the Dian Lake. Chemical waste, soil erosion, and the introduction of non-native fish and frogs rendered the newt’s habitat uninhabitable.
While the Yunnan Lake newt was still commonly observed in the 1950s, a targeted search in 1979 failed to locate any individuals. The species has not been seen since, and in 2004, the IUCN officially declared the Yunnan Lake newt extinct.
5. Saudi Gazelle

The Saudi gazelle (Gazella saudiya) was native to the arid deserts and semi-deserts of the Arabian Peninsula. Its range included sandy and rocky plains with scattered acacias, stretching from Kuwait to Yemen.
The primary cause of its extinction was excessive hunting. The availability of firearms and off-road vehicles in the 20th century led to uncontrolled hunting, pushing the already rare species to the brink. Additionally, habitat loss due to expanding settlements and agricultural development further contributed to its decline.
The last confirmed sightings of the Saudi gazelle in the wild occurred in the 1970s. By 1980, it was officially declared extinct in the wild. Genetic analyses of gazelles held in captivity later revealed that these were not pure Saudi gazelles but hybrids of other gazelle species. To date, no pure specimens have been found in the wild or in captivity. The species has been officially listed as extinct by the IUCN since 2008.
6. Cuban Ivory-billed Woodpecker

(© Huub Veldhuijzen van Zanten/Naturalis Biodiversity Center, CC BY-SA 3.0, via Wikimedia Commons)
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 ancient forests provided ideal conditions, with numerous dead and decaying trees housing beetle larvae, the bird’s primary food source.
Large-scale deforestation for agriculture and timber at the beginning of the 20th century caused a dramatic loss of habitat. The woodpecker retreated to remote mountain regions in eastern Cuba, but even these refuges were heavily impacted by additional deforestation in the 1950s and 1980s. Targeted hunting, particularly during breeding seasons, further reduced the already declining population.
The last confirmed sighting of the Cuban ivory-billed woodpecker was in 1987 in the Ojito de Agua mountains. Despite the area’s subsequent protection, the species remained untraceable. Extensive searches, most recently in 2010 and 2011, yielded no evidence of its survival. Despite occasional reports of potential sightings or calls, the Cuban ivory-billed woodpecker is widely considered extinct today.
7. Maui ‘akepa

(© Hiart, CC0, via Wikimedia Commons)
The Maui ʻakepa (Loxops ochraceus) was a small songbird native to the Hawaiian island of Maui, inhabiting the lush rainforests and dry koa forests in the higher elevations of the Haleakalā volcano.
Like many Hawaiian bird species, the Maui ʻakepa faced severe threats from introduced species. Mosquitoes carried diseases such as avian malaria and avian pox, to which native birds had no immunity. Additionally, invasive plants like blackberries displaced native vegetation, leading to food shortages. Other introduced species, such as frogs and insects, disrupted the food chain, further contributing to the bird’s decline.
The Maui ʻakepa population began to shrink noticeably in the early 20th century. By the 1970s, sightings had become rare, and the bird eventually vanished. The last confirmed sighting occurred in 1988 within the Hanawi Natural Area Reserve. Despite extensive searches and conservation efforts, the species was not found again. In 2023, the Maui ʻakepa was officially removed from the endangered species list and declared extinct.
8. Golden Toad

(© U.S Fish and Wildlife Service – colour corrected, degrained and sharpened by diegogmx, Public domain, via Wikimedia Commons)
The golden toad (Incilius periglenes), distinguished by its striking bright orange coloration, was restricted to a small area in the Monteverde Cloud Forest of Costa Rica. Its range covered only a few square kilometers, making it particularly vulnerable.
Several factors contributed to the extinction of the golden toad. The El Niño event of 1986/87 caused severe droughts, drying up the breeding pools critical for its reproduction. Simultaneously, the chytrid fungus (Batrachochytrium dendrobatidis), which infects amphibians’ skin, spread rapidly, proving fatal to many individuals. This combination of climatic and disease-related impacts hit the species hard.
In the early 1980s, the golden toad was still abundant, with thousands gathering during breeding season. However, the population plummeted in 1987: out of 43,500 recorded eggs, only 29 tadpoles survived. By 1989, just one male was observed, marking the species’ last sighting. Despite extensive search efforts, the golden toad has not been found since, and in 2004, the IUCN officially declared it extinct.
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 primarily attributed to the loss of wetlands essential for breeding and resting. Many of these habitats were converted into agricultural land or drained, particularly in North Africa and the Middle East. Additionally, hunting and insufficient protection at key stopover sites further pressured the declining population. Climate change also played a role, altering conditions along migration routes and reducing food availability.
The last confirmed sighting of a slender-billed curlew occurred in 1995 in Morocco. In the following years, there were unconfirmed reports of occasional sightings, but none were substantiated by evidence. As no further individuals were found despite extensive surveys in the suspected habitats, the species was officially declared extinct in 2024.
10. Catarina Pupfish
The Catarina pupfish (Megupsilon aporus) was a small freshwater fish native to a single spring in southwestern Nuevo León, Mexico. First described in 1972, it grew to a maximum length of about four centimeters and was notable for lacking pelvic fins.

(© Fishspeciation, CC BY-SA 4.0, via Wikimedia Commons)
In the early 1990s, its habitat began drying up due to overuse and water extraction for agricultural purposes. Simultaneously, invasive species further threatened the already endangered population. By 1994, the spring had completely dried up, and the Catarina pupfish was declared extinct in the wild. In a rescue attempt, some individuals were kept in aquariums during the late 1980s and early 1990s. However, breeding proved extremely challenging, and the captive population 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 Potosi pupfish (Cyprinodon alvarezi) produced offspring, but they did not survive long. With the death of the last male in 2014, the species was officially lost.
11. Yellow-tipped O’ahu Tree Snail

(© Naturalis Biodiversity Center, CC0, via Wikimedia Commons)
The tree snail Achatinella apexfulva, once native to the Hawaiian island of Oʻahu, was not only the first scientifically described snail of Hawaii but also the first snail species of the archipelago to be officially declared extinct. Its fate is closely tied to its last known individual, the endling “George,” who became a global symbol of biodiversity loss.
The decline of A. apexfulva resulted from habitat destruction, invasive species, and extensive snail collection. Deforestation for agriculture and settlements, coupled with the spread of invasive plant species, irrevocably altered Oʻahu’s forests. Introduced predators like the rosy wolfsnail (Euglandina rosea) and rats further preyed upon the native snails. In the 19th century, the collection of these snails’ colorful shells for traditional jewelry had already significantly reduced their populations.
In 1997, the remaining individuals were brought into a breeding program, but all offspring died except for one – George. He lived in the University of Hawaii’s laboratory until his death in 2019. Without a mate to reproduce with, the species became extinct with George’s passing.
What Can We Learn from Extinction?
These eleven animal species are emblematic of the countless others lost over recent decades. Their disappearance illustrates the devastating impact of human activities on nature. Habitat destruction, invasive species, and climate change have drastically weakened global biodiversity. Alarmingly, many species are only discovered when they are already endangered.
Yet, these examples also offer hope. Successful conservation programs have demonstrated that it is possible to stabilize populations and save species from extinction – if there is both the will and the resources for long-term action. The so-called Romeo error reminds us not to give up on species prematurely, as even the smallest chance of survival can lead to recovery.
Our Role in Conservation
Protecting endangered species and their habitats is a responsibility that falls on all of us. Scientists and conservation organizations cannot halt biodiversity loss alone. Each of us can contribute – whether by supporting conservation projects, promoting sustainable lifestyles, or being mindful of natural resource use. Education about the importance of biodiversity is also vital to prevent further losses.
The extinction of these eleven animals serves as a warning – and a call to action. It is our responsibility to protect the remaining richness of life and ensure that future generations inherit a planet brimming with biodiversity.
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