SAFE: A Formula to Decide Which Endangered Species Have the Best Shot

A new formula proposes to determine which endangered animals are salvageable so we can focus our resources–and abandon the ones that can’t be saved.


There are hundreds of animals on the IUCN Red List–the definitive list of animals that are threatened with extinction. On the other hand, there is a limited amount of money in the world dedicated toward animal conservation. If we can’t save them all, how do we decide which to save? A new formula called the SAFE (Species Ability to Forestall Extinction) Index aims to bring some triage to the conservation movement, so that we can focus our money on rehabilitating the species most likely to survive.

There are a number of individuals that an animal population needs to maintain in order to have a chance at survival. Below that number, while they might continue to hang around for a while at low population numbers, they’re simply too susceptible to disaster or continued environmental change to ever claw their way back to viability. And they aren’t actually contributing anything to an ecosystem; the environmental damage is already done, even though official extinction hasn’t yet happened. Is working to save those animals a waste of money when all the money could be going to places where it could actually bring an animal back from the brink?

If you think it is, then the SAFE is for you. If you care about rhinos (paging Marc Ecko), you might find it helpful to know that the Sumatran rhino has a SAFE score of –1.36, while the Javan has a score of –2.10. Negative numbers are worse, and any species scoring less than zero is quite bad, but the Sumatran has a better chance of success. If conservationists pooled their rhino-earmarked money there, we might be able to fully save one species, instead of merely prolonging the agony of two.

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[Image from Flickr user dhruvaraj]

Read More: Prospects for the World’s Endangered Species Rest on Peace and Harmony of the Human Species

About the author

Morgan is a senior editor at Fast Company. He edits the Ideas section, formerly