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Caving for bones

How a tip from a citizen scientist led to deep discoveries in Utah’s caves.

Scientists from the Natural History Museum of Utah have taken a deep dive into the not-so-distant past thanks to a friendly tip from Utah’s caving community. In a paper published this week by the Journal of Mammalogy, five scientists from the Natural History Museum of Utah (NHMU) and colleagues from Utah’s caving community have published the first research from their collaborative fieldwork effort deep in Utah’s caves.

The journal’s feature article reveals why caves make such compelling research archives; what was uncovered in Boomerang Cave in northern Utah; why skeletal remains provide new access to hard-to-get data from the recent past; and offers a new zoological baseline for mammalian changes in an alpine community.

A an with a helmet on holds out a mummified rat that looks like a rock with some bones embedded.


Kaedan O’Brien, lead author and anthropology Ph.D. candidate at the University of Utah, holds up a mummified wood rat at an undisclosed cave in the House Range of western Utah.

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“To understand the impacts of climate on alpine ecosystems, we record current mammal species—mostly through trapping. But that method doesn’t tell us anything about the mammalian diversity in the recent past,” said Kaedan O’Brien, lead author and anthropology PhD candidate at the University of Utah. “So not a lot of study has been done on past alpine ecosystems because they are harder to get to, and when you do there is a slim chance of finding older skeletal remains intact.”

In NHMU Chief Curator and paleoecologist Dr. Tyler Faith’s words, “We want to know what animals were there in the 1800s, but that’s nearly impossible in the absence of historical records. How do we document the recent past without a time machine?” An out-of-the-blue email from local caver and study co-author Eric Richards offered an unexpected method of time travel: repelling hundreds of feet down into Utah’s caves to find what may have fallen in—and when.

PHOTO CREDIT: Eric Richards

Dr. Tyler Faith, NHMU’s chief curator, rappels off a cliff ledge in Rock Canyon near Provo, Utah, to access a cave entrance where an NHMU research team was examining animal bones.

In early 2019, Richards emailed NHMU Curator of Paleontology Dr. Randy Irmis to ask if he or the museum had any interest in the animal bones that he’d been finding on Utah cave adventures, and he sent photographs. Irmis replied right away, including colleague Dr. Tyler Faith and O’Brien, a PhD student in Faith’s lab. The group met, hit it off, and after a couple of trial outings for equipment training, Faith and Irmis were lowering themselves into caves to collect bones of by-gone animals.

“To be clear, this project would have never happened without the cavers reaching out to us, and investing time, and training with us. Eric and his wife Fumiko literally ‘showed us the ropes.’” said Faith. “I hope people realize that research isn’t just done by scientists who work at the museum, it can be public collaboration—in this case with trained experts (do not try this at home).”

A small cave enclosure. A silhouette of a man facing away in the foreground, and two men with headlamps looking at bones in the background.


From left to right, Dr. Randall Irmis, NHMU’s curator of paleontology, Dr. Tyler Faith, NHMU’s chief curator, and caver Tom Evans examine and collect mammal bones on the floor of Tubafore Cave.

After Faith obtained a research permit from the U.S. Forest Service in September 2019, Richards took the team to Boomerang Cave in the Bear River Range where they collected specimens for lab analysis at the museum. O’Brien managed the lion’s share of that work, upon which the paper is based.

“Identifying skeletal remains is painstaking work, because you just go bone by bone, sorting by size and element, and then comparing them with regional museum voucher specimens,” said O’Brien. But the result is exciting.

Using radiocarbon dating, fossils found in Boomerang Cave were shown to span the past 3,000 years, with the bulk from the last 1000 years or so. Comparison of these fossils to museum records and present-day mammals collected by co-authors and NHMU zoologists, Dr. Eric Rickart and Katrina Derieg, showed that the cave provided a faithful reflection of mammal diversity in the area. Perhaps most exciting is that the fossils also revealed the presence of species unknown to the region, like Merriam’s shrew. The full list of fossils is in the current Journal of Mammalogy, along with more on why this research matters.

A spotlight lights up an elk skeleton on the floor of a dark cave. A scientist with a headlight helmet examines examines the skeleton.


Dr. Tyler Faith, NHMU’s chief curator, examines elk bones inside Skeleton Cave in the Uinta Mountains, Utah. Faith and a research team from NHMU collected bones from the site but left the elk skeleton in place given that it is the namesake of the cave.

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“Our work highlights the value of collecting skeletal remains from caves as a convenient and accurate method for understanding the mammal communities” said Irmis. “Caves help us create comprehensive and long-term records and better understand how animals have changed in the recent past.”

Faith, Irmis, and O’Brien credit the ongoing success of this research to the curiosity and generosity of Utah’s caving community. It’s another example of citizen science advancing research and developing long-term relationships between NHMU and the public. To learn more about citizen science opportunities with NHMU, please visit


About the Natural History Museum of Utah 

The Natural History Museum of Utah is one of the leading scientific research and cultural institutions in the country. Established in 1963, the museum’s 10 permanent exhibitions are anchored by its state-of-the-art collections and research facilities containing almost 2 million objects. These collections are used in studies on geological, biological, and cultural diversity, and the history of living systems and human cultures within the Utah region. The museum hosts approximately 300,000 general visitors a year and provides one of the most spectacular private event settings in the Salt Lake City area. NHMU also broadens the reach of its mission through a variety of science-based outreach programs to communities and schools throughout Utah, reaching every school district in the state every other year.