Should We Bring Back Extinct Species?

The idea of bringing extinct species back to life is known as “de-extinction,” and it’s now a legitimate scientific field. By extracting DNA from museum specimens and splicing it into the cells of similar living species, scientists say they can engineer animals back into existence. Researchers have started thinking seriously about which extinct species to focus their efforts on. Near the top of most lists are the woolly mammoth, which lived in the Arctic and went extinct about 4,000 years ago, and the passenger pigeon, which was once the most common bird in North America but went extinct in 1914.

But just because scientists may be able to bring species back doesn’t mean they should. Two scientists debate the ethics of de-extinction.

December 11, 2017

Reviving an extinct species may sound like something out of Jurassic Park, but the science of de-extinction is real. It’s not possible to bring back dinosaurs because they’ve been extinct too long and their DNA is no longer salvageable. But new genetic technologies enable us to re-create more recently extinct species like passenger pigeons and woolly mammoths. Thinking of Jurassic Park, you might think de-extinction is threatening, but bringing back certain species has benefits.

De-extinction could play a key role in healing damaged ecosystems, because it’s actually just an extension of good old-fashioned conservation work—the protection of existing animals and their environments. Conservationists have already had success returning living species to areas where they’ve died out. One example is the return of wolves to Yellowstone National Park. Their extermination a century ago led to environmental problems, such as the decline of certain trees. But just 20 years after conservationists returned wolves to Yellowstone, the ecosystem is much healthier. That’s because by eating elk, wolves give tree saplings a chance to grow. The young trees attract beavers, which make dams that draw birds and amphibians. More species thrive in the park today than when wolves were missing. De-extinction can do the same in other places.

De-extinction could play a key role in healing damaged ecosystems.

Finding wolves for Yellowstone was easy since they still lived in other places. But what about a species that no longer exists anywhere on Earth? De-extinction lets us bring them back too. More than 3 billion passenger pigeons once lived in North America’s forests. Their immense flocks created the diverse woodland habitats needed by hundreds of plants and animals. Since their extinction, diversity in forests has declined substantially, leaving many species struggling. Bringing back passenger pigeons would help save today’s threatened species.

Not every extinct species will survive in modern times, and even fewer serve important roles for conservation. We need to focus on bringing back those critical extinct species that will help other living species.

—BEN J. NOVAK

Lead Researcher, Revive & Restore

Scientists believe somewhere between 200 and 2,000 species become extinct every year—many more than official counts record. And that number could be even higher. By the time you go to bed tonight, one, 10, or maybe more species that have been on Earth for millions of years will be gone forever.

Although de-extinction has been touted as a way of reversing this horrible trend, this argument doesn’t hold up. For the millions of dollars it would cost to bring one species back from extinction and support it in the wild, we could save dozens more species from going extinct in the first place. Because scientists have limited resources, a decision to do one thing is a decision not to do another: A decision to spend millions on resurrecting one species is a decision to neglect others and allow them to go extinct.

The process of bringing back an extinct species is not only expensive, it’s risky. In most cases, the habitat for the extinct species people want to resurrect is gone or seriously altered. Mammoths, for example, went extinct after the Arctic began warming 10,000 years ago. It’s much warmer there now than it was then, and it’s getting hotter every year. The most likely result of bringing back extinct species is that we’d find ourselves trapped in a cycle where we would need to spend more and more money just to keep their tiny populations alive.

Bringing back an extinct species would be expensive and risky.

Those who support bringing back extinct species will say that doing so will help support other species. But we already have many important species—such as elephants, tigers, and rhinos—that are in serious trouble. Why not work on keeping them alive? They’ll also argue that by resurrecting an extinct species, we’ll learn many lessons on genetics and breeding. But we can learn exactly the same lessons by working on trying to save living species. There’s also the risk that reintroducing long-extinct species will actually hurt the environment if these species spread out of control.

The evidence is overwhelming: De-extinction is not a good investment for the environment. It may well be interesting science, but it’s not conservation.

—JOSEPH BENNETT