Great Basin Naturalist


A late Pleistocene mammalian fauna from Little Box Elder Cave, eastern Wyoming, provides paleontological evidence bearing on several contemporary and related studies in zoogeography of Recent intermontane mammals and on understanding of rapidly changing environments in the Rockies in late Pleistocene and post-Pleistocene time. Both paleontological and zoogeographical findings suggest that during glacial periods in the Pleistocene the life-zones were lowered and, therefore, many boreal mammals ranged away from the glaciated Rocky Mountain chain. Since then, some of these returned or retreated northward as the climate moderated, and many warmth-adapted mammals approached the Rockies. The fossil and Recent faunas analyzed together reveal that the post-Pleistocene climate became so warm that numerous boreal species disappeared from habitats that are now again boreal (montane). Some warmth-adapted species have advanced to and retreated from the cave area. The climatic optimum, as well as the glacial and interglacial periods, apparently affected the distribution of numerous mammals in this area.