When Paul Martin looked across the desert landscape near the University of Arizona he saw a very different world, at least in his mind's eye. As an expert on the end of the Pleistocene epoch, which ended around 13,000 years ago, he saw North America awash with animals that are no longer here.
He saw elephants, and camels, and cheetahs, and horses, roaming freely across the continent. These native animals disappeared either long before humans arrived, or just as the first Americans entered the scene.
Martin, now retired from Arizona, began talking with friends about what it would be like to restore some of that magic to a land that has lost some of the great beasts that once dominated the landscape.
He went so far as to propose that some effort be made to reintroduce some of those extinct animals, or at least their closest-living relatives.
"The idea did not attract much attention," says Harry Greene, professor of ecology and evolutionary biology at Cornell University. But sometime later Greene was discussing Martin's vision with one of his graduate students, Josh Donlan, now a doctoral candidate at Cornell.
That discussion led to a meeting at a New Mexico ranch of experts from across the country, including Martin, to discuss what may be one of the boldest proposals to come out of the environmental movement in decades.
The result was a commentary written by Donlan and published in the prestigious journal Nature.
In that report, 11 contributors called for the reintroduction of elephants and cheetahs and other extinct animals in a long-range program that would result in some species roaming freely across the land, just as they had thousands of years ago.
They called it "Pleistocene Rewilding."
The result was predictable, although Greene admits even he was somewhat taken aback. Some folks just thought it was a terrific idea. Others, including some leading conservation organizations, thought it was awful.
"One guy called me a pointy headed academic," says Greene, who prior to this had led a fairly quiet life as an expert on snakes. "I've never gotten hate mail before."
Dolan says some people accused the scientists of wanting to play God, recreating a land that has changed much since the late Pleistocene. They cite examples of human meddling that led to disaster. Right on Martin's doorstep, for example, Arizona officials reintroduced the crayfish a few years ago, and they've since spent millions trying to bring it under control.
Little wonder that ranchers, who pale at the thought of a coyote (not to mention wolves) didn't look fondly on the idea of lions and cheetahs prowling through their area.
But not all of the response was negative, especially the feedback from folks who had taken the trouble to read Donlan's commentary.
"It's been completely all over the map," Greene says. Favorable editorials, and comments from some members of the National Academy of Sciences, described the proposal as "forward looking."
Although some news reports indicated that elephants, as well as cheetahs and other fierce predators from Africa, might soon be set free to drag people out of their beds at night, that's not at all what the researchers had proposed.
The re-introduced animals would be in tightly-controlled environments, and the program would be phased in over decades, and begin relatively small. Think turtles. But not little turtles.