Why scientists are cloning black-footed ferrets

In February 2021, a group of scientists announced a major breakthrough in conservation: they had cloned a black-footed ferret, an endangered species native to the American West.

Elizabeth Ann, the clone, was delivered via C-section on December 10, 2020, and as of this writing is still thriving thanks to the work of nonprofit Revive & Restore, the US Fish and Wildlife Service, and other partners. She is the first successful clone of an endangered species, and the culmination of years of cutting-edge work attempting to use cloning to rescue vulnerable populations.

The black-footed ferret is often the center of stories like this. Conservation specialist Kimberly Fraser calls the rescue of the ferret some 40 years ago “the greatest American story we have in conservation.”

Before September 26, 1981, the ferret — a 19-to-24 inch-long, 1.4-to-2.5 pound predator that mostly targets prairie dogs in the United State’s Western plains — was not just considered endangered; it was considered extinct.

Soon afterward, scientists called to the scene found a small colony of 18 ferrets near a farm in Wyoming. They’ve been a conservation priority ever since. Now, there’s a concerted effort by the Black-Footed Ferret Conservation Center in Wellington, Colorado, run by the federal Fish and Wildlife Service and supported by the government and some private partners, to reintroduce the species to the wild.

All reintroduction programs run into problems, but black ferrets have faced one whopper of a problem: the bubonic plague. Going by the decidedly less exciting name of “sylvatic plague” when it infects prairie dogs and ferrets, the disease is spread by the ferret’s food (those prairie dogs) and while some species of ferret are immune to the disease, the black-footed ferret is not.

On a 2018 episode of the Future Perfect podcast, Vox’s Byrd Pinkerton and I investigated some methods scientists were then pondering to save the ferrets, from plague vaccines to using CRISPR to achieve plague resistance, and we debate whether all the effort is worth it. The cloning effort is just the latest in this series, and so far a particularly exciting one.

All else being equal, we should save every endangered species. But we know the plains ecosystem can get on without the black-footed ferret; it largely has for the past few decades during which the species has been in captive breeding. And there are plenty of other problems that need money. Why should this one stand out?

I started out our journey really skeptical of the value of saving the ferrets. But Byrd, and the scientists we talked to, did a lot to convince me. Be sure to listen, and see if you’re sold too.

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