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Michael O'Connor PhD

Michael O'Connor, MD, PhD

Chair, Institutional Animal Care and Use Committee
Department of Biodiversity, Earth and Environmental Science
Department of Biology
Office: PISB 318
Phone: 215.895.2637
Lab Location (Dry): PISB 503
Lab Phone: 215.895.6906
Lab Location (Wet): PISB 501 H1
Lab Phone: 215.895.6890


  • PhD, Colorado State University, 1989. Advisor: C.R. Tracy
  • Residency, Internal Medicine, Vanderbilt University, 1981-1984
  • MD, Johns Hopkins University, 1981
  • BA, LaSalle College, 1977

Curriculum Vitae:

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Research Interests:

  • Thermal, hydric, & energetic effects on the activity and distribution of reptiles and amphibians
  • Physical constraints on heat and mass exchange by reptiles and amphbians
  • Physiological and physical constraints on gas exchange in sea turtle nests - effects on metabolism and development


I am a professor in both the Department of Biodiversity, Earth and Environmental Science (BEES) and the Department of Biology. I teach courses in Ecology, Physiological and Biophysical Ecology, Human Physiology, and Biostatistics.

My research combines my love of biology (particularly physiology and ecology), mathematics, and complex systems, and has always been strongly tinged by the appreciation of the complex workings of various physiological systems that I picked up during my days in medicine. Nearly always I am trying to use some quantitative tool to tease out new ideas about how some animal can meet environmental challenges and survive and grow in its environment. Usually, those challenges involve some physiological or even purely physical stressor that the animal must conquer to live and be active in its habitat. I like to work with others, typically collaborate on projects, and rarely publish single-author papers.

Recurrent themes in my research are: 1) physical stressors like heat or dehydration, 2) ectothermic (cold- blooded) animals, 3) goals the animal must meet to live / survive / grow, and 4) mechanistic models of how the stressors constrain the animal’s ecology, and how they can circumvent those constraints. Thus, I have studied: how frogs control body temperature and more importantly water loss in stressful environments; how reptiles (and others) use blood flow to control rates of warming and cooling; how temperatures constrain the ecology of tortoises and sea turtles. Recently, I’ve been working with others to try to understand how body size constrains the metabolism and ecology of animals, because we think currently popular theories miss some important points.

Fun extraneous fact - I have a third-degree black belt in karate.

Selected Publications:

  • Radzio, T.A., N.J. Blase, J.A. Cox, D.K. Delaney, and M.P. O'Connor. 2019. Behavior, growth, and survivorship of laboratory-reared juvenile gopher tortoises following hard release. Endangered Species Research 40: 17–29,
  • O'Connor, M.P. and S. O'Donnell. 2018. Implications of iterative communication for biological system performance. Journal of Theoretical Biology 436:93-104.
  • Radzio, T.A. and M.P. O'Connor. 2017. Behavior and temperature modulate a thermoregulation- predation risk tradeoff in juvenile gopher tortoises. Ethology 12:957-965.
  • Neeman, N., J.R. Spotila and M.P. O'Connor. 2014. A simple, physiologically-based model of sea turtle remigration intervals and nesting population dynamics: effects of temperature. Journal of Theoretical Biology 380:516-523.
  • Sieg, A.E., M.P. O'Connor, J.N. McNair, B.W. Grant, S.J. Agosta, and A.E. Dunham. 2009. Mammalian metabolic allometry: Do intraspecific variation, phylogeny, and regression models matter? American Naturalist 174: 720-733.
  • Honarvar, S., M.P. O'Connor, and J.R. Spotila. 2008. Density-dependent effects on hatching success of the olive ridley turtle, Lepidochelys olivacea. Oecologia 157(2):221-30.
  • O'Connor, M.P., S. J. Kemp, S. J. Agosta, F. Hansen, A. E. Sieg, B. P. Wallace, J. N. McNair, A. E. Dunham. 2007. Reconsidering the mechanistic basis of the metabolic theory of ecology. Oikos 116: 1059-1073.
  • O'Connor, M.P., S.J. Agosta, F. Hansen, S.J. Kemp, A.E. Sieg, J.N. McNair, A.E. Dunham. 2007. Phylogeny, regression, and the allometry of physiological traits. American Naturalist 170:431–442.
  • O'Connor, M.P., A.E. Sieg, and A.E. Dunham. 2006. Linking physiological effects on activity and resource use to population level phenomena. Integrative and Comparative Biology 46:1093–1109.
  • Dzialowski, E.M. and M.P. O'Connor. 2004. Importance of the limbs in the physiological control of heat exchange in Iguana iguana and Sceloporus undulatus. Journal of Thermal Biology 29:299–305.
  • O'Connor, M., L.C. Zimmerman, E.M. Dzialowski, and J.R. Spotila. 2000. Operative temperature models for moderate to large sized ectotherms - reduction of heterogeneity in model temperatures. Journal of Thermal Biology 25:293-304.
  • O'Connor, M.P. and P. Dodson. 1999. Biophysical constraints on the thermal ecology of dinosaurs. Paleobiology 25:341-368.
  • O'Connor. M.P. 1999. Physiological and ecological implications of a simple model of heating and cooling in reptiles. Journal of Thermal Biology 24:113-136.
  • Penick, D.N., J.R. Spotila, M.P. O'Connor, A.C. Steyermark, R.H. George, C.J. Salice, and F.V. Paladino. 1998. Thermal independence of muscle tissue metabolism in the leatherback turtle, Dermochelys coriacea. Comparative Biochemistry and Physiology A 120A:399-403.
  • Zimmerman, L.C., M.P. O'Connor, S. Bulova, J.R. Spotila, S.J. Kemp, and C.J. Salice. 1994. Thermoregulation by desert tortoises in the eastern Mojave Desert: Seasonal patterns of operative and body temperatures, and microhabitat utilization. Herpetological Monographs 8:45-59.
  • Paladino, F.V., M.P. O'Connor, and J.R. Spotila. 1990. Metabolism and heat exchange in the leatherback sea turtle: A warm turtle in a cool ocean. Nature 344:858-860.