Natural Trap Cave in Wyoming is revealing hundreds of fossils left over from the last ice age, according to an archaeological team examining the geological feature.
The cave holds the remains of tens of thousands of animals that fell to their deaths over thousands of years. Remains in the cave include large animals like bison, as well as small creatures, such as lizards, rodents and snakes.
"We found evidence of bison, a bit of gray wolf and quite a lot of cheetah and horse," Julie Meachen, a paleontologist with Des Moines University who finished a two-week excavation of the cave on 8 August, said.
Natural Trap cave lies in the base of the Bighorn Mountains of northwestern Wyoming, and was first discovered by scientists in the 1970's. The federal government quickly shut down exploration of the cave for safety reasons, and this is the first time in four decades paleontologists have been allowed in the natural feature.
This new dig uncovered around 200 large bones from a wide variety of species, including samples from American cheetahs. The youngest of these recently-discovered artifacts is roughly 12,000 years old, while the oldest are nearly twice that age. A vast number of smaller fossils, from birds, rodents and lizards were also recovered during the 14-day study. Many of the species recovered from the site went extinct at the end of the last ice age, between 10,000 and 12,000 years in the past.
Animals fell into the cave through a semi-hidden hole in the ground, 15 feet from side to side. The unfortunate creatures then plummeted 85 feet to their deaths, to a rock floor, measuring 120 feet across. There, cold, camp conditions preserved the animal remains for the ages. The cave formed long ago from the collapse of limestone, which created the deadly trap that provides the feature with its name.
Meachen descended into the cave ten times over the course of the archaeological dig.
"Some bones still have collagen with intact DNA for genetic testing and some fossils are fragments crushed by rocks. But we take it for what it is when we find it," Meachen told the press.
During the course of the excavation, a pack of rats fell into the cave and perished on the bone-riddled floor. A deer mouse also dropped into the underground chamber, but survived the fall. The tiny creature was sent back to the surface, where it received medical care.
Study of fossils from Natural Trap Cave could reveal new information about the biology and climate at the end of the most recent ice age.