Gary McCracken


1976 – Ph.D., Cornell University

Research Interests

Population biology, molecular ecology, animal behavior, conservation biology, and the ecology of infectious diseases.

My research concerns the distribution of animals in space, their behavior and interactions, and resulting impacts on genetic population structure. Currently, the organisms are bats, insects, and fungal and viral pathogens. The projects in my lab involve field studies combined with molecular assays, and ongoing collaboration with The Institute for Ecological Modeling at UTK to better inform data collection and to provide predictive analysis and interpretation.

Long-term research interests in my lab involve resource distributions and foraging behaviors of bats and linking the foraging ecology and movements of bats with migration patterns of insects, including major insect crop pests. These efforts employ a variety of field techniques that include acoustic and video studies of the feeding behaviors of bats at ground level and higher altitudes, monitoring the abundances of bats and insects in space and time, and molecular assays of the diets of bats. Collaborative research with the US Department of Agriculture on the aerial dispersal, population dynamics, and availability of major insect pests allows us to assess the ecosystem services provided by insect-eating bats over agricultural and natural landscapes.

Our research interests also concern infectious disease in bats. Our research on the ecological influences on rabies infections in bats strives to better understand the factors that influence the circulation of rabies virus within bat populations. Other research strives to better understand, predict, and ameiliorate the impact of the White Nose Syndrome (WNS) epidemic on North American populations of bats. Research conducted in collaboration with Tom Hallam and others involves empirical and modeling efforts to investigate and predict the geographic spread of the pathogenic fungus Geomyces destructans (Gd) that causes WNS. Other studies focus on behaviors of bats inside and outside of winter roost sites that may affect the differential susceptibility of bats to the disease. This research involves field seasonal surveillance for Gd infections in natural populations of bats that differ in population structure and behavior. Field studies on WNS are conducted in collaboration with federal and regional conservation management agencies and colleagues at several Universities in the US and Canada.


  • Federico P, Hallam TG, McCracken GF, Purucker ST, Grant WE, Correa Sandoval AN, Westbrook, JK, Medellin RA, Cleveland CJ, Sansone CG, Lopez JD Jr, Betke M, Moreno-Valdez A, Kunz TH. 2008. Brazilian free-tailed bats (Tadarida brasiliensis) as insect pest regulators in transgenic and conventional cotton crops. Ecological Applications 18: 826-837.
  • Gillam, E.H., N. Ulanovsky, and G.F. McCracken. (2007) Rapid jamming avoidance in biosonar. Proceedings of the Royal Society of London B. 274:651-660.
  • McCracken, G.F. E. Gillam, J. Westbrook, Y-F Lee , M. Jensen & B. Balsley. 2008. Brazilian free-tailed bats (Tadarida brasiliensis: Molossidae: Chiroptera) at high altitude: links to migratory insect populations. Integrative & Comparative Biology 48:107-118.
  • Turmelle, A.S., L.C. Allen, B.A. Schmidt-French, F.R. Jackson, T.H. Kunz, G.F. McCracken & C.E. Rupprecht. 2009. Ecology of rabies virus exposure in colonies of Brazilian free-tailed bats (Tadarida brasiliensis) at natural and man-made roosts in Texas. Vector-Borne and Zoonotic Diseases doi:10.1089/vbz.2008.0163.
  • Gillam, E.H.; McCracken, G.F; Westbrook, J.K.; Jensen, M. & B.B. Balsley. 2009. Bats aloft: variation in echolocation call structure at high altitudes. Behav. Ecol. Sociobiol. 64:69-79.
  • Streicker, D.G., A.S. Turmelle, M.J. Vonhof, I.V. Kuzmin, G.F. McCracken, and C.E. Rupprecht. 2010. Host phylogeny constrains cross-species emergence and establishment of rabies virus in bats. Science 329: 676-679.
  • Hallam, T.G. and G.F. McCracken. 2011. Culling and the management of the panzootic White Nose Syndrome in hibernating bats. Conservation Biology 25: 189-194.
  • Russell, A.L. Cox, M.P., Brown, V.A., and McCracken, G.F. 2011. Population growth of Mexican free-tailed bats (Tadarida braziliensis Mexicana) predates human agricultural activity. BMC Evolutionary Biology 11:88
  • Brown, V.A., A. Brooke, J.A. Fordyce, and G.F. McCracken. 2011. Genetic analysis of populations of the threatened bat Pteropus marianus. Conservation Genetics DOI 10.10007/s10592-011-0196-y
  • Boyles, J.G., Cryan, PM, McCracken G.F., and Kunz T.H. 2011. Economic importance of bats to agriculture. Science 332: 341-342.