The loss of species represents the permanent disappearance of a unique genetic lineage from the planet. Biological extinction occurs when the last individual of a species has died, signifying an irreversible end to that form of life. This natural process is currently accelerating at a rate far exceeding historical norms, leading many scientists to conclude the world is experiencing a sixth mass extinction event. Understanding which species are vanishing helps to frame the global biodiversity crisis.
How Scientists Confirm Extinction
The declaration of a species as extinct is the result of a rigorous scientific review process guided by international bodies. The International Union for Conservation of Nature (IUCN) maintains the Red List of Threatened Species, which provides the global standard for assessing a species’ conservation status. A species is only moved to the “Extinct (EX)” category after exhaustive, systematic surveys have been conducted throughout its historical range, failing to record a single individual.
This process often means a species may have been gone for decades before it is officially declared extinct. A transitional category, “Critically Endangered (Possibly Extinct),” is used when a species is highly likely to be extinct, but further searches are warranted. The formal designation of extinction in a given year, such as 2020, reflects the finalization of these extensive reviews and the official update of the Red List documentation, acknowledging a loss that often occurred years or even centuries prior.
The Animals Declared Extinct in 2020
The 2020 update to the IUCN Red List formally recognized the extinction of 31 species, highlighting losses across diverse taxa in various global locations. Among the confirmed losses was the Smooth Handfish (Sympterichthys unipennis), a marine species native to the waters off Tasmania, Australia. This fish, which used its pectoral fins to “walk” along the seafloor, had not been seen since 1802 and is considered the first marine bony fish declared extinct in modern history.
A devastating series of losses involved 17 freshwater fish species endemic to Lake Lanao and its outlet in the Philippines. Fifteen of these species were formally listed as Extinct, including several species of the Barbodes genus. These fish were last reliably sighted decades ago, with some disappearing as far back as the 1960s and 1970s.
Amphibians also suffered a setback with the declaration of extinction for three Central American frog species, including the Splendid Poison Frog from Panama. The official listing of these amphibians followed a period of dramatic declines across Central and South America.
Another species added to the extinct list was the Bonin Pipistrelle (Pipistrellus sturdeei), a bat known only from a single specimen collected in the 19th century in Japan. Due to its limited documentation and failure to be rediscovered, the species was moved from the “Data Deficient” category to “Extinct” in the 2020 assessment.
Driving Factors Behind the Losses
The factors contributing to the 2020 extinction declarations are typical of the threats facing species worldwide, often involving a combination of human-driven pressures. The massive loss of endemic fish in Lake Lanao, for instance, was primarily driven by the introduction of non-native, predatory fish species. This biological invasion, coupled with overharvesting and destructive fishing practices like dynamite fishing, completely destabilized the unique lake ecosystem.
For the Smooth Handfish, its demise was linked to a mix of historical and ongoing impacts in its shallow marine habitat. Causes included habitat destruction from bottom fishing practices, pollution, and the unintentional capture of the fish (bycatch). Even though the local fishery collapsed over 50 years ago, the cumulative damage proved irreversible for the species.
The Central American frog extinctions are a direct consequence of the infectious disease chytridiomycosis. This fungal pathogen affects amphibians globally and is a significant driver of decline. Habitat loss, caused by deforestation and the conversion of natural landscapes for agriculture and development, represents a continuous pressure on species across all regions. The losses confirmed in 2020 underscore the powerful, multifaceted influence of human activity on the natural world, whether through the introduction of disease, habitat alteration, or resource overexploitation.