Born To Rewild


North America is a land shaped by elephants. (And pronghorns like the one above — but more on that later.)

10,000 years ago — a blink of the evolutionary eye — members of the elephant family like mammoths and mastodons roamed our grasslands, influencing nearly every plant and animal that lived there.

They were part of one of the greatest assemblages of large mammals to ever roam the earth, with great herds that rivaled those of Africa.

Giant sloths and tapirs, wild camels and horses, cheetahs and lions: All thrived here.

Some conservation biologists believe it’s time to bring them — or at least ecologically similar species — back to America.

Pleistocene rewilding, as this idea is called, is frequently placed in the same wacky camp as UFO investigations and Bigfoot biology.

It is almost impossible for critics, including Conservancy scientists, to discuss it without mentioning Jurassic Park.

But maybe Pleistocene rewilding shouldn’t be so quickly dismissed.

Conservationists frequently point to the ecologically important roles played by fire, rivers, wetlands and climate. Large animals can also play an important role in shaping whole landscapes.

We know, for instance, the prairie is much healthier with bison herds.

Large herds of mammoths, wild horses and camels shaped the landscape  dramatically — as the evidence increasingly demonstrates. Connie Barlow’s book The Ghosts of Evolution describes many now marginal plants in North America (like osage orange and honey locust) that evolved to be dispersed by feeding elephants.

The pronghorn — the only true North American Pleistocene mammal to remain — evolved to outrun cheetahs. Today it races only ghost predators.

But didn’t the large Pleistocene mammals “naturally” go extinct?

That’s a subject of some debate, but paleoecologists like Paul Martin present strong evidence that the large mammals were wiped out quickly by the first humans to enter the continent.

The animals had not evolved with humanity like the large animals of Africa, and were quickly eliminated — what is called the overkill hypothesis.

Tapirs and camels belong here as surely as bison and grizzly bears. While many of the Pleistocene species are extinct, ecologically similar species remain. South American camels — like guanacos and vicunas — could easily be reintroduced to grasslands.

Even Indian elephants — yes, elephants — could play the role of mammoths and mastodons.

We don’t have to start big with something like, say, releasing elephants across the continent. That, obviously, is akin to Jurassic Park.

But we could start small. As Joel Berger of the Wildlife Conservation Society writes: “No one can deny historical niches are unfilled today…Why not a humble beginning — say, on a hundred fenced hectares, or a thousand, or even ten thousand?”

Why not? Such a beginning could reveal important new insights about North American ecological processes — and help bring home our continent’s true diversity of large animals.

(Photo: Pronghorn, alone on the range. Credit: Matt Miller.)

If you believe in the work we’re doing, please lend a hand.


  1. Playing God is dangerous… people tend to forget that THAT particular job is taken (and even if it were vacant, who’d be qaulified?) North America is having a hard enough time managing the species it already has. Reintroducing descendents of the Pleistocine era animals could lead to unseen ecological dangers. Does the phrase “cane toad” mean anything to anyone? The species that have developed in Africa, India and other parts of Asia should stay where they are.

  2. Most of our endangered species are in trouble because of loss of habitat. The government is killing wild horses to try to ensure that “native” species can survive. Do you seriously think that we have room for a bunch of imported species?

  3. But maybe Pleistocene rewilding shouldn’t be so quickly dismissed.

    Yes it should.

    I think Pleistocene rewilding should get in line behind Holocene rewilding. Once we get that squared away, we can talk about introducing the analogs of animals that lived in North America before the last Ice Age.

    We can’t just add elephants to Oklahoma and call it Pleistocene-ic. What were the predators? And their predators? We have even less of an idea how those ecosytems worked than we do of how our current ones do.

  4. Oh, come on! We have enough to do with managing invasive species, protecting current native species, and controlling overdevelopment. Focus, people.

  5. In some ways, the rewilding experiment is already being done. In Texas, there are many game ranches that promise a “safari” experience. While most of these ranches focus mainly on huntable exotic antelope, some do include rhinos, cheetahs, and giraffes.

  6. Speaking of big cats and “rewilding,” does TNC have any news on the jaguar that was euthanized in Arizona after being captured and released with a radio collar?

  7. The earth is pregnant and she is about to give birth. Think of the pain a woman, who does no drugs during child birth, it is painful to watch, this is whats happening to mother earth. She is heating up in the center of her core! Rejoice for her, do not let the physical world and its illusions make you worry. This happens every 65,000 years.

  8. Yes, if we want to ‘re-wild’ with elephants and camels, etc., let’s not forget sabre-toothed tigers, and other such mega-predators. Seriously, looking at the re-introduction of wolves into the Northern Rockies, we’d better be careful with more tinkering.

  9. And just how much of North America (frankly, my United States) has the wonderful combination of space, habitat, food, and lack of human incoveniences such as towns, highways and barbed-wire fences? What farmer wants them trampling his cultivated land? Roadkill anyone? Welcome to WINTER anyone? Shortsighted, self-indulgent reporting.

  10. I actually think it could be a good idea. Maybe not with elephants, but with other smaller animals. Humans are the ones who made them disappear in the first place and we should put them back.

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