Caley Orr
Associate Professor • Department of Cell and Developmental Biology, CU Anschutz Medical Campus • Affiliated faculty (Anthropology)
Department of Anthropology

CU Anschutz Medical Campus
13001 E. 17th Place, Rm. N5207A

Aurora, CO 80045

Office Hours:
By Appointment


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 has been excavating 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.

I teach human gross anatomy in the Master of Science Program in Modern Human Anatomy and in the professional health science programs (School of Medicine and School of Dental Medicine) at CU Anschutz. I am happy to advise anthropology graduate and undergraduate students with interests in paleoanthropology and primate comparative morphology.

2021  Bowland LA, Scott JE, Kivell TL, Patel BA, Tocheri MW, Orr CMHomo naledi pollical metacarpal morphology shaft morphology is distinctive and intermediate between that of australopiths and other members of the the genus Homo. Journal of Human Evolution 158:103048

2018  Orr CM. Kinematics of the anthropoid os centrale and the functional consequences of scaphoid-centrale fusion in the African apes and hominins Journal of Human Evolution 114:102-117.

2017  Orr CM. Locomotor hand postures, carpal kinematics during wrist extension, and associated morphology in anthropoid primates. The Anatomical Record 300:382-401.

2016  Orr CM. Functional morphology of the primate hand: recent approaches using biomedical imaging, computer modeling, and engineering methods. In Kivell TL, Lemelin P, Richmond BG, Schmitt D (eds): The Evolution of the Primate Hand: Anatomical, Developmental, Functional and Paleontological Evidence. Springer. pp 227-257.

2015  Kivell TL, Deane AS, Tocheri MW, Orr CM, Schmid P, Hawks J, Berger LR, Churchill SE. The hand of Homo naledi. Nature Communications 6:8431.

2015  Berger LR, Hawks J, de Ruiter DJ, Churchill SE, Schmid P, Delezene LK, Kivell TL, Garvin HM, Williams SA, DeSilva JM, Skinner MM, Musiba CM, Cameron N, Holliday TW, Harcourt-Smith W, Ackermann RR, Bastir M, Bogin B, Bolter D, Brophy J, Cofran ZD, Congdon KA, Deane AS, Dembo M,Drapeau M, Elliott MC, Feuerriegel EM, Garcia-Martinez D, Green DJ, Gurtov A, Irish JD, Kruger A, Laird MF, Marchi D, Meyer MR, Nalla S, Negash EW, Orr CM, Radovcic D, Schroeder L, Scott JE, Throckmorton Z, Tocheri MW, VanSickle C, Walker CS, Wei P, Zipfel B. Homo naledi, a new species of the genus Homo from the Dinaledi Chamber, South Africa. eLife 4:e09560.

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.

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.

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.

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.

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