CHEYENNE, Wyoming — For the first time in three decades, paleontologists are about to revisit one of North America’s most remarkable troves of ancient fossils: The bones of tens of thousands of animals piled at the bottom of a sinkhole-type cave.
Natural Trap Cave in Wyoming is 25 meters deep and almost impossible to see until you’re standing right next to it. Over tens of thousands of years, many, many animals — including now-extinct mammoths, short-faced bears, American lions and American cheetahs — shared the misfortune of not noticing the 4-meter-wide (15 feet) opening until they were plunging to their deaths.
Now, the U.S. Bureau of Land Management is preparing to reopen a metal grate over the opening to offer scientists what may be their best look yet at the variety of critters that roamed the foothills of the Bighorn Mountains during the planet’s last glacial period around 25,000 years ago.
Paleontologist Julie Meachen said she has been getting ready to lead the international team of a dozen researchers and assistants by hitting the climbing gym.
“I’m pretty terrified,” Meachen admitted Wednesday.
She hasn’t done any real climbing before, she said, and the only way in is to rappel down. The only way out is an eight-story, single-rope climb all the way back up.
The cave is perpetually cold and clammy, with temperatures about 5 degrees Celsius and humidity around 98 percent. Even the Bureau of Land Management paleontologist Brent Breithaupt, who isn’t one to fear lots of animal bones, describes the hole as a tad creepy.
“One can only hope that, as a researcher, you’re able to leave,” said Breithaupt, who visited the cave as a college student the last time it was open to scientists. “It’s an imposing hole in the ground. But one that actually has very important scientific value.”
Some mammal remains from the cave could be over 100,000 years old, Breithaupt said.