When it comes to protecting the biodiversity of Planet Earth, there is no greater failure than extinction. Thankfully, only a few dozen species have been officiallydeclared extinct by the US Fish and Wildlife Service in the half-century since the passage of the Endangered Species Act.

But, hold on. Aren’t we in the middle of the sixth mass extinction? Shouldn’t the list of extinct species be… way longer? Well, yeah. Maybe.

Producer Taylor Quimby sets out to understand why it’s so difficult to officially declare an animal extinct. Along the way, he compares rare animals to missing socks, finds a way to invoke Lizzo during an investigation of an endangered species of crabgrass, and learns about the disturbing concept of “dark extinctions.”

Editor's Note: This episode was first published in October 2022. Since then, the US Fish and Wildlife Service officially delisted 21 of 23 proposed species due to extinction. The ivory-billed woodpecker was not one of them.

Featuring Sharon Marino, Arne Mooers, Sean O’Brien, Bill Nichols, and Wes Knapp.