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Bakken, George


Ph.D., Rice University

Phone: 812-237-2396
Office: Science Building 265bakken.jpg

Research Interests: physiological ecology; biometeorology; evolution; thermoregulation.

My studies investigate the behavioral and physiological responses of animals to outdoor microclimates. The ability of an animal to perform essential tasks varies with body temperature. Temperature regulation requires the expenditure of time, energy, and water. Thus, the thermal environment often determines when and where animals may be active, how well they perform, how much food and water is needed, and the amount of energy available for growth and reproduction.

Some of the current projects that my students and I are working on include thermoregulatory physiology of swimming ducklings, thermal image studies of hibernation and arousal patterns in Indiana bats, the use of the infrared-sensitive pit organ for thermoregulatory behavior by rattlesnakes, and spatially explicit thermal mapping studies of lizard habitat.

Our laboratory studies examine behavior and physiological performance of animals at various body temperatures, as well as their energy and water use under various combinations of air temperature, wind, and simulated sunlight. The objective is to quantify the value of specific responses to sun and wind that regulate body temperature or minimize energy or water use. Field studies involve simultaneous measurement of micrometeorological data and observations of habitat selection and the frequency of thermoregulatory, social, and foraging behaviors. The results of the laboratory and field studies together give improved understanding of the role of climate in the ecology and behavior of the species of interest.

I have two well-equipped laboratories with a total of 1400 square feet. My equipment includes wind tunnels and flow tanks and full respirometry instrumentation to measure O2, CO2, and H2O exchange. For both field and lab studies, we use a FLIR PM 575 thermal imager for remote body temperature measurement (above, right). I can field up to 4 complete micrometeorology stations measuring air temperature, humidity, wind, and solar and thermal radiation. My laboratories are supplemented by shared use facilities, including 2x4 and 4x4 field vehicles, a new controlled climate chamber facility with 7 walk-in chambers, and a small but well-equipped machine shop.

Selected Publications

Bakken, G. S.. 2011 online, 2012 print.  Is it necessary to paint metabolism chambers black?  Journal of Thermal Biology 37: 100-102.  doi:10.1016/j.jtherbio.2011.11.006

Bakken, G. S., S. E. Colayori and T. Duong. 2012.  Analytical methods for the geometric optics of thermal vision illustrated with four species of pitvipers.  Journal of Experimental Biology 215:2621-2629. doi:10.1242/jeb.063495 [cover article 1 of 2]

Kohl, T., S. E. Colayori, G. Westhoff, G. S. Bakken and B. A. Young. 2012.  Directional sensitivity in the thermal response of the facial pit in western diamondback rattlesnakes (Crotalus atrox).  Journal of Experimental Biology 215:2630-2636. doi:10.1242/jeb.065896 [cover article 2 of 2]

Rockweit, J.T., A.B. Franklin, G.S. Bakken,  R.J. Gutierrez.  2012.  Potential Influences of Climate and Nest Structure on Spotted Owl Reproductive Success: A Biophysical Approach.   PLoS-ONE 7(7):e41498.  doi:10.1371/journal pone.0041498.

VanSant, M. J.  and G. S. Bakken. 2006. Thermoregulation on the air-water interface II: foot conductance, activity metabolism and a two-dimensional heat transfer model. Journal of Thermal Biology 31: 491-500. doi:10.1016/j.jtherbio.2006.05.002

Bakken, G. S., M. R. Banta, C. M. Higginbotham, A. J.  Lynott. 2006. It’s just ducky to be clean: the water repellency and water penetration resistance of swimming mallard ducklings. Journal of Avian Biology 37: 561-571,

Bakken, G. S. 2007. A critique of thermal modeling of snake infrared reception by Jones, Lynn, and Stone (2001). Journal of Theoretical Biology 244: 167-168. doi:10.1016/j.jtbi.2006.07.028

Bakken, G. S. and A. R. Krochmal. 2007. The imaging properties and sensitivity of the facial pits of pitvipers as determined by optical and heat transfer analysis. Journal of Experimental Biology 210: 2801-2810. doi:10.1242/jeb.006965

Boyles, J. A. and G. S. Bakken, 2007. Seasonal changes and wind dependence of thermal conductance in dorsal fur from two small mammal species (Peromyscus leucopus and Microtus pennsylvanicus) Journal of Thermal Biology 32: 383-387. doi:10.1016/j.jtherbio.2007.04.007

Banta, M. R., A. J. Lynott, M. J. Van Sant, and G. S. Bakken. 2004. Partitioning heat loss from mallard ducklings swimming on the air-water interface. Journal of Experimental Biology 2004 207: 4551-4557.

Krochmal, A. R., G. S. Bakken, and T. J. LaDuc. 2004. Heat in evolution's kitchen: evolutionary perspectives on the functions and origin of the facial pit of pitvipers (Viperidae: Crotalinae) Journal of Experimental Biology 207: 4231-4238.

Krochmal, A. R. and G. S. Bakken. 2003. Thermoregulation is the pits: use of thermal radiation for retreat site selection by rattlesnakes. Journal of Experimental Biology 206: 2539-2545. [featured in Science News, 163:388]

Galligan, E. W.,  G. S. Bakken, and S. L. Lima. 2003. Using a thermographic imager to find nests of grassland birds. Wildlife Society Bulletin 31:865-869.

Bakken, G. S., J. B. Williams, and R. E. Ricklefs. 2002. Metabolic response to wind of downy chicks of arctic-breeding shorebirds (Scolopacidae). Journal of Experimental Biology 205: 3435-3443.

Bakken, G. S., A. F. Boysen, C. E. Korschgen, K. P. Kenow, and S. L. Lima. 2001. Design and performance of a rugged standard operative temperature thermometer for avian studies. Journal of Thermal Biology 26: 595-604.