Pop quiz: How many endangered species can you name? Odds are, your list is something like: tigers, rhinos, gorillas, orangutans, pandas. If you’re a diehard endangered species aficionado, you may have even said Amur leopard, black rhino, mountain gorilla, Bornean orangutan — ah, but not giant pandas, which were upgraded from “endangered” to “vulnerable” a few years ago.
When I set out to write this story, all I wanted to know was which species are actually closest to extinction. Which ones really might vanish tomorrow? Turns out, that’s a terribly complicated question.
The official, exhaustive endangered species list is maintained by the International Union for Conservation of Nature — the IUCN’s (in)famous Red List. Of the 120,356(!) plants, animals and fungi the group has assessed, 882 are declared extinct, 6,807 are critically endangered, and 11,731 are just endangered. These determinations are based on a number of variables and rankings. Since nobody wants to read a list of “The 18,000 (or So) Most Endangered Species,” I decided to narrow things down by focusing on critically endangered vertebrates — animals with backbones, such as birds, reptiles, amphibians, mammals and fish. There are 1,983 critically endangered vertebrate species.
Species can earn a “critical” badge for many reasons. If their population size has been reduced a certain amount over a certain time period. If their geographic range has shrunk a bunch. If their individual population sizes are small or shrinking. They can also be critically endangered if the species is down to fewer than 50 individuals. That earns the species an IUCN “D” rating, which never looks good on a report card. Currently, there are 235 Ds.
I downloaded the IUCN dataset and started going through each species to see what their story was. Turns out over 200 of the 235 might already be extinct — these are animals like the Siamese Bala-shak, a fish last seen in Thailand in 1974, or the Guanacaste Hummingbird, which apparently is only known from a specimen collected in — wait for it — 1895.
