My research interests are in the evolutionary history, functional morphology and systematics of ungulates. A major part of my work examines postcranial skeletal correlates of habitat, body size and locomotor behavior in living ungulate mammals. Such morphological correlates can provide accurate ecological profiles of extinct ungulates. These profiles are used to examine fossil ungulate communities, to gain information about their vegetational habitat, and to track changes in vegetation over time. I am particularly interested in Tertiary climatic changes in North American, especially the Miocene savannah fauna with its many similarities to modern East Africa. A second part of my work analyzes the relationships among fossil and living ungulates, primarily ruminant artiodactyls, using morphological characteristics. One of the primary objectives of this work is to clarify the relationships among the fossil and living ruminants, and to attempt to clarify relationships of ruminants to other artiodactyls. I am particularly interested in studying the applicability of postcranial characteristics to phylogenetic analysis of ungulates, since these remains are plentiful and have not been widely used in this group; some consistent differences among families have been identified which promise to be useful in phylogenetic analysis.