Natural Trap Cave is a pit cave in the Bighorn Mountains, in northern Wyoming, United States. Excavations in the cave are an important source of paleontological information on the North American Late Pleistocene, due to a rich layer of fossils from animals that became trapped in the cave. Location The cave is located northeast of Lovell, Wyoming, at an elevation of . It is a bell-shaped pit or sinkhole within the Madison Limestone, deep, with an opening by at the top, and a diameter of around at the bottom. Early explorations The first investigation of its animal remains was initiated in 1970 by Lawrence Loendorf of the University of Missouri, who initially collected some fossils, and began an excavation in 1971. Besides bones, one Native American red jasper knife was found below the entrance drop and a wooden artifact, possibly an atlatl shaft, was discovered in a rat's nest below some talus. In 1972, Carol Jo Rushin (University of Montana) with a grant from the National Speleological Society and a four-person team and logistical support provided by Dr. Loendorf, excavated a 10 x 10-foot wide pit at the bottom of the entrance drop, southwest of the pit excavated in 1971. The pit was dug to a depth of six feet. Late Pleistocene to recent bones from 20 species of mammals and five bird species were recovered, including a dire wolf, ancient horse, and mammoth. Ms. Rushin's Master's thesis "Interpretive and Paleontologic Values of Natural Trap Cave, BigHorn Mountains, Wyoming" (1973) addressed the interpretive, anthropologic, paleontologic, and geologic aspects of the cave. A short article regarding this research also appeared in the December, 1972 issue of the National Speleological Society News. Further excavations were conducted throughout the 1970s by the University of Missouri and the University of Kansas. Remains of animals which have fallen into the sinkhole since the last ice age lie over deep at the bottom of the pit. Small mammals whose remains have been found in the cave include pikas, jackrabbits, cottontail rabbits, marmots, chipmunks, Peromyscus mice, woodrats, Microtus voles, and collared lemmings. Larger mammals represented in the cave include Canis species, red foxes, short-faced bears, weasels, martens, wolverines, American cheetahs, American lions, Equus species, Camelops, deer, antilocaprids, bison, bighorn sheep, and mammoths. Remains of the American cheetah are particularly abundant in the cave. 2014 explorations The entrance to the pit was covered with a safety grill by