Figure 4.  Relative abundance of arvicoline lineages from strata of the Pit.  Climatic inferences on the right are based on abundances of Lemmiscus curtatus and Mictomys sp. Reproduced with permission from A.D. Barnosky, ed., Biodiversity Response to Climate Change in the Middle Pleistocene: The Porcupine Cave Fauna from Colorado, © 2004 by The Regents of the University of California.