Over the past several decades, thousands of species have been determined to be extinct or at risk of extinction due to human activity. But in some cases, scientists lack conclusive proof that species are extinct. Those species are considered “lost”, a distinction reserved for animals that haven’t been observed in at least 50 years.
A new international study that includes researchers from SFU suggests there are 562 lost species that are designated as “possibly extinct” in the International Union for Conservation of Nature Red List of Threatened Species.
Of the lost species, 257 are reptiles, 137 are amphibians, 130 are mammals and 38 are birds. Most of the lost species are in countries with high biodiversity like Indonesia, Mexico and Brazil.
“The fact most of these lost species are found in megadiverse tropical countries is worrying, given such countries are expected to experience the highest numbers of extinctions in the coming decades,” said study lead author Tom Martin from the UK’s Paignton Zoo.
The red list only shows species as “extinct” when there is no reasonable doubt that the last species has died, but that distinction is often difficult to verify.
Only 311 terrestrial vertebrate species have gone extinct, meaning there are 80 per cent more lost species than have been declared extinct. Being lost doesn’t necessarily mean that species have been wiped out. Some species, like the Miles’ robber frog of Honduras, were thought to be extinct, but were later rediscovered.
Researchers recommend focusing search efforts on megadiverse regions to determine whether the lost species are extinct. Though more funding for such searches is required.