If returning the Greater Yellowstone Ecosystem’s native species is truly a priority, the nation’s first national park would be teeming with more than grizzly bears, wolves and huge bison with prehistoric genes.

There also would be a thriving population of giant mammoths calling the ecosystem home.

And if a group of ambitious genetic scientists have anything to say about it, Yellowstone tourists will one day have to navigate mammoth jams on their trips through the park along with its majestic bison and bears.

That now-extinct mammoths could have a future home in Yellowstone isn’t just a sci-fi fantasy, it could happen. But whether it should is a conundrum as hairy as the prehistoric pachyderms, and some scientists think that concept should be kept on ice.