Bramble Cay melomys, golden toads, Tasmanian tigers, Caribbean monk seals and, of course, the dodo. These are all species that we know to be extinct – as far as scientists know, the last individual of the species has died. But what about the likes of Sir David’s long-beaked echidna, that hasn’t been seen in 61 years? Or the Togo mouse that hasn’t been seen in 132 years? These species aren’t confirmed to be extinct, but when do we stop searching and accept that we won’t rediscover them?
New research has recently been published investigating the global distribution of ‘lost’ species – those that have not been seen for over 50 years, but are not yet declared extinct. Dr Tom Martin, Zoo Evidence Officer at Wild Planet Trust, led the research, working alongside authors G.C. Bennett, A. Fairbairn and A.O. Mooers. Dr Martin quoted:
“This is the first study to examine how many lost vertebrate species there are globally, and the first to explore in detail why these lost species are important for wildlife conservation.”
The research found 562 ‘lost’ species of vertebrate, comprising 257 reptiles, 137 amphibians, 130 mammals and 38 birds. Most of the newly declared ‘lost’ species inhabited tropical areas, but they were also found in more temperate countries like China and USA, ranging in size from shrews to freshwater dolphins to wild cattle. Dr Martin is concerned about the conservation implications of these lost species:
“There are nearly twice as many lost species as there are extinct species, and we believe this may be causing confusion when it comes to calculating extinction rates and identifying conservation priorities.”
In short, lost species make it difficult for scientists to know how many species are going extinct. While mistakenly listing species as extinct can result in ‘Lazarus’ species (those that are declared extinct but later found), not recognising them as extinct masks the problem at hand, restricting us from understanding the gravity of the situation facing our species. This makes it hard to decide which conservation projects require immediate attention.
The only way to find out whether these species really are extinct is to go looking for them. This research calls for more expeditions to be funded so that these species can be looked for:
“We recommend that conservation organizations support fieldwork projects to try to find these lost species, or indeed to determine whether they are in fact likely to be extinct, as an important future priority.”
The full article can be read at https://zslpublications.onlinelibrary.wiley.com/doi/full/10.1111/acv.12788.
Image: Miles’s Robber Frog (Craugastor milesi): a ‘lazarus’ species found only in one small patch of Honduran cloud forest. It was classified as extinct by the IUCN in 2004 but rediscovered again four years later. Credit: Tom Brown.