A treasure trove of the remains of hundreds of mammals from the Ice Age has been discovered in a cave in Wyoming.
The ancient sinkhole is believed to have opened up 25,000 years ago, trapping a large number of unsuspecting creatures who fell into it over the course of thousands of years, and whose remains were preserved in the cool, dark conditions.
Many are large animals that became extinct thousands of years ago, including the North American lion and American cheetah. Smaller mammals have also been unearthed, such as fully preserved skeletons of tiny rodents.
Natural Trap Cave, at the base of the Bighorn Mountains in northern Wyoming, had been unexplored for more than 30 years. Australian and American researchers, who had to rappel down a 26m drop to reach the bottom of the hole, began their latest excavation after a number of mammal bones rose to the surface.
The cave is on land belonging to the US Bureau of Land Management, and was first discovered by palaeontologists in the 70s. The fossils of mammoths, short-faced bears, collared lemmings and camels were unearthed under layers of sediment. But researchers now believe that they represent only a fraction of the remains waiting to be discovered and hope that they may yet find mammals dating back as far as 100,000 years.
