Natural Trap Cave

A Window into Wyoming's Past

10/3   Natural Trap Cave, a Window into Wyoming’s Past”. Presented by Gretchen Hurley, Geologist, Bureau of Land Management, Cody Office.

A window into Wyoming’s Ice Age past – Natural Trap Cave in the Big Horn Mountains offers unparalleled insights into the Wyoming of the late Pleistocene, of animal life that frequented our state but in many instances is now long extinct.

Natural Trap Cave is a 15-foot wide by 90-foot deep vertical opening that formed in ancient limestones uplifted during formation off the northern Bighorn Mountains over millions of years. During the Pleistocene Epoch and continuing into the Holocene, numerous different species and specimens of Ice Age mammals fell into this cave, typically died on impact, and were beautifully preserved, almost as though they were refrigerated. Most of the mammals trapped in this cave are extinct now, including American Cheetah, American Lion, Columbian Mammoth, Short-faced Bear, Beringian Wolf, Bison, Camels, Musk-Ox, and several types of Ice Age horses. But several of the species found in this cave are still living in the area today, including modern Pronghorn, rodents, coyotes, fox, and Bighorn Sheep, among others. This extremely rare collection of preserved Ice Age fauna is providing researchers a unique look at Ice Age ecosystems and paleoclimates, as well as allowing refinement of information on Pleistocene mammalian DNA and evolution during a critical time in the history of our planet.  


Paleontological excavations in this treasure trove were first conducted between the late 1970’s through the late 1980’s, revealing a wealth of excellent data on mammalian taxa living in Wyoming during Pleistocene time. After this research concluded, the cave was closed and gated by the Bureau of Land Management’s Cody Field office for 34 years between 1989 and 2014.   Then, for four summers between 2014 and 2017, Natural Trap Cave was reopened to allow paleontologists Dr. Julie Meachan (Univ. of Des Moines, Iowa), and Dr. Alan Cooper (University of Adelaide, Center for Ancient DNA) and their teams to excavate specimens for a broad range of scientific study. Entry into the cave was only possible using single rope technique, which was overseen by the researchers and a skilled team of volunteer cavers from area grottos. The recent research project in Natural Trap Cave is managed by BLM geologist Gretchen Hurley of the Cody Field Office. Hurley will discuss the general geology and paleontology of this rare, world-class cave, and provide a summary of the recent research project including some of the preliminary findings which are beginning to be revealed. Video