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Caley Orr, Ph.D.

Associate Professor

Caley Orr Anschutz Modern Human Anatomy
 Ph.D., Anthropology, Arizona State University, 2010

Graduate Program Affiliations:

Dr. Orr is a paleoanthropologist and comparative anatomist who teaches human anatomy in the Masters of Science Modern Human Anatomy program and in the professional health science programs at CU Anschutz. His research focuses primarily on the origins and evolution of key human adaptations including bipedality and tool use. This work involves lab study of primate morphology and the hominin fossil record along with paleontological and archaeological fieldwork relating to deep human prehistory.

As a paleoanthropologist and comparative anatomist, I am interested in understanding the adaptations and phylogenetic relationships of our early ancestors and the sequence, timing, and causes of the major events in human biological and cultural evolution.

Habitual bipedality and the intensification of tool behaviors represent two of the key adaptive signatures of the human lineage, and explaining their origins has long been a focus of inquiry in anthropology. The evolutionary histories of these adaptations are intertwined due to the emancipation of the forelimb granted by upright posture; thus, I have focused most of my attention on the morphology of the hands and feet in humans and nonhuman primates and fossil hominins (early human ancestors).

Understanding the evolutionary transformation of the postcranial skeleton in the human lineage requires 1) reconstructing the mode of locomotion that preceded the origins of bipedality; 2) revealing constraints imposed by that ancestral condition; and 3) identifying subsequent morphological changes and their functional significance for novel behaviors (e.g., tool making and use). Most of my research tackles various aspects of this agenda.

chimp wrist kinematics Caley orr


In the lab, I address these questions through traditional anatomical study of bones, fossils, and cadaveric material coupled with quantitative bioengineering and computer science approaches. These methods include computed-tomography-based analysis of joint kinematics, surface laser scanning and three-dimensional morphometrics, electromyography, measurement of muscle moment arms, and broad-based comparative studies of primates and nonprimate mammals..

Another aspect of my work involves the recovery and description of new paleontological and archaeological material relating to human origins. Most recently, our international collaborative team has been excavating Arma Veirana—a new late Pleistocene site in northern Italy that we expect will provide important information about how modern Homo sapiens came to replace archaic hominin populations (e.g., Neanderthals) by approximately 40,000 years ago. Previously, fieldwork and/or study of museum fossil collections has taken me to Bulgaria, Ethiopia, Kenya, South Africa, France, Spain, and southwestern Wyoming, to work in early and late time periods of human evolution.

Arma Veirana Caley Orr

Archaeological excavation at the Neanderthal and modern human site of Arma Veirana, northwestern Italy.