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Caley M. Orr

Assistant Professor​Dr. Caley Orr

Cell and Developmental Biology
Ph.D., Anthropology, Arizona State University, 2010

Research Interest​

Paleoanthropology, evolution of hominin bipedality, adaptation to manual manipulation and tool behaviors, primate functional morphology (focus on hands and feet), biomechanics, 3D morphometrics, biomedical imaging and computer modeling for virtual human and comparative anatomy


Office Location: Building 500, Room N5209D

Mailing Address:

Mail Stop F435
13001 17th Place
Aurora, CO 80045

Phone: 303-724-0517

Departmental Affiliations

Cell and Developmental Biology

Graduate Program Affiliations

Modern Human Anatomy Program


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. In particular, 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.

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 initiated a project at 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., Neandertals) 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.

For information on specific projects:


2015 Goodenberger KE, Boyer DM, Orr CM, Jacobs RL, Femiani JC, Patel BA. Functional morphology of the hallucal metatarsal with implications for grasping ability in extinct primates. American Journal of Physical Anthropology 156:327-348.

2015 Almecija S, Orr CM, Tocheri MW, Patel BA, Jungers WL. Exploring phylogenetic and functional signals in complex morphologies: the hamate of extant anthropoids as a test-case study. The Anatomical Record 298:212-229.

2015 Knigge RP, Tocheri MW, Orr CM, McNulty KP. Three-dimensional geometric morphometric analysis of talar morphology in extant gorilla taxa from highland and lowland habitats. The Anatomical Record 298:277-290.

2014 Dunn RH, Tocheri MW, Orr CM, Jungers WL. Ecological divergence and talar morphology in gorillas. American Journal of Physical Anthropology 153:526-541.

2013 Orr CM, Tocheri MW, Burnett SE, Due Awe R, Saptomo W, Sutikna T, Jatmiko, Wasisto S, Morwood MJ, Jungers WL. New wrist bones from Homo floresiensis (Liang Bua, Flores). Journal of Human Evolution 64:109-129.

2011 Tocheri MW, Solhan CR, Orr CM, Femiani J, Frohlich B, Groves CP, Harcourt-Smith W, Richmond BG, Shoelson B, Jungers WL. Ecological divergence and medial cuneiform morphology in gorillas. Journal of Human Evolution 60:171-184.

2010 Orr CM, Leventhal EL, Chivers SF, Marzke MW, Wolfe SW, Crisco JJ. Studying primate carpal kinematics in three-dimensions using a computed-tomography-based markerless registration method. The Anatomical Record 293:692-709. -Invited paper for a special issue on primate functional morphology

2010 Marzke MW, Tocheri MW, Steinburg B, Femiani JD, Linscheid RL, Orr CM, Marzke RF. Comparative 3D quantitative analyses of trapeziometacarpal joint surface curvatures among living catarrhines and fossil hominins. American Journal of Physical Anthropology 141:38-51.

2009 Larson SG, Jungers WL, Tocheri MW, Orr CM, Morwood MJ, Sutikna T, Awe Due R, Djubiantono T. Descriptions of the upper limb skeleton of Homo floresiensis. Journal of Human Evolution 57:555-570.

2008 Tocheri MW, Orr CM, Jacofsky MC, Marzke MW. The evolutionary history of the hominin hand since the last common ancestor of Pan and Homo. Journal of Anatomy 212:544-562.

2007 Tocheri MW, Orr CM, Larson SG, Sutikna T, Jatmiko, Saptomo EW, Awe Due R, Djubiantono T, Moorewood MJ, Jungers WL. The primitive wrist of Homo floresiensis and its implications for hominin evolution. Science 317:1743- 1745.
-This paper was recognized with a 2007 Science Achievement Award by the Smithsonian Institution

2007 Orr CM, Delezene LK, Scott JE, Tocheri MW, Schwartz GT. The comparative method and the inference of venom delivery systems in fossil mammals. Journal of Vertebrate Paleontology 27:541-546.

2006 Wolfe SW, Crisco JJ, Orr CM, Marzke MW. The dart-thrower’s motion of the wrist: is it unique to humans? The Journal of Hand Surgery [American] 31:1429-1437.

2005 Orr CM. The knuckle-walking anteater: a convergence test of adaptation for purported knuckle-walking features of African Hominidae. American Journal of Physical Anthropology 128:639-658

2001 Orr CM, Dufour DL, Patton JQ. A comparison of anthropometric indices of nutritional status in Tukanoan and Achuar Amerindians. The American Journal of Human Biology 13:301-309.​​

Link to PDFs: