When Julie Meachen and Rachel Dunn went digging, so did media outlets around the globe: Both assistant anatomy professors spent part of the summer in Wyoming’s Big Horn Mountains, foraging for fossils as part of major research expeditions. Meachen was featured in stories and interviews on Reuters, multiple National Public Radio stations, the BBC World Service and others on her two-week dig at Natural Trap Cave, an 85-foot-deep sinkhole that trapped prehistoric animals during the Pleistocene Epoch and amazingly preserved their fossils in the cool and clammy cavern.
Dunn and her fossil-hunting colleagues were led by Amy Chew, Ph.D., assistant professor of anatomy at Western University of Health Sciences, and Ken Rose, Ph.D., professor in the Center for Functional Anatomy and Evolution, Johns Hopkins University School of Medicine. They were featured by the news service WyoFile and various other media for their dig in the Bighorn Basin, a 100-mile-long
valley in Wyoming that’s full of mammal bones from the Eocene epoch. A dramatic increase in temperature during the period – nine to 14 degrees Fahrenheit – over thousands of years led to the extinction of many species found in the basin. In fact, nowhere is the geology of the epoch more available than across the basin.
Dunn, who also joined Meachen’s team for part of its expedition, and her fellow researchers were looking back at the Eocene epoch to help find answers about how climate change will affect modern animals. Meachen and her crew are focused on the late Pleistocene Epoch, commonly referred to as the Ice Age; they’re extracting DNA from the remains they recovered to gather new insights into the climate, diets, genetic diversity and extinction of animals during the epoch.
Her road to Wyoming had its bumps. The Bureau of Land Management (BLM), the authority over Natural Trap Cave that permitted her dig, had instructed her to rent a high-clearance vehicle for the arduous 18-mile trek from the highway to the cave; however, it failed to advise her to bring a four-wheel-drive one, so her supplies had to be shuttled to and from the cave and camp by others. Onsite was a group of local cavers who had e-mailed Meachen earlier expressing a desire to join the dig; they raised concerns by some of her colleagues that they would be “a bunch of yahoos who would tromp all over the fossils,” she says.
In addition, two sessions on a central Iowa rockclimbing wall had done little to allay her nervousness about rappelling into the bell-shaped cave.
Fortunately, all three situations were soon resolved. BLM staff helped shuttle gear and allowed Meachen to stash in a shed the group’s tents, a camping stove and other non-dig-related items, giving her more room in her vehicle to bring home fossils. The cavers gave valuable advice on rappelling in and out of the cave and helped haul out 60-pound buckets of dirt. And when the time came for her first descent, she says, her attitude was “okay, let’s do this.”
“The cave looks dark when you look in. It feels like you’re going into the abyss,” says Meachen, who managed the 85-foot drop in seven minutes. “But the cave itself is amazing. The 15-foot hole at the top lets light in to illuminate the entire cave. It’s very beautiful, with walls of different colors from moss, mold and water.”
Her group discovered a treasure trove of fossils of all sizes, from large-animal bones – now being washed and sorted or held in cold storage at DMU – to “micro-fossils,” such as mouse teeth, bird bones and lizard jaws. They also uncovered riddles: How did recovered remains of fish and frogs get down there? Why were bones in disarticulated jumbles rather than skeletons? Why did most fossils come from one layer of the cave?
“There are so many questions relating to that cave,” Meachen says. “We got so many things out, but we barely scratched the surface.”
Those questions will draw Meachen back to Natural Trap Cave next summer. She anticipates the group will include paleontologists and other scientists, cavers, students and at least one high school teacher, a friend, who plans to blog about the expedition for his students. She’ll be equipped with more knowledge about what to bring and a typed-up summary from the cavers on ways to make the dig go even more smoothly. In the meantime, she’s grateful for the experience and the 30 or so colleagues who joined her.
“Our crew was awesome,” she says. “I was really pleased with how the dig turned out. Now we can work out the kinks for when we go back.”