Conservation & Science Staff Bios

Rachel Santymire, Ph.D.

Davee Center for Epidemiology and Endocrinology


  • Ph.D.- Environmental Science and Policy, George Mason University
  • M.S. - Animal Physiology, Clemson University
  • B.S. - Pre-veterinary Science, Clemson University

Areas of Expertise

  • Reproductive physiology
  • Conservation biology
  • Evolutionary biology of reproductive processes (specifically ovulation and spermatozoa production)
  • Evolutionary biology of stress adaptation
  • Ecosystem health
  • Small population biology

About Rachel Santymire:

Always the oddball in the animal production class, Rachel began her career thinking about how to adapt techniques designed for domestic species to conserving wildlife. While everyone was researching livestock production, she was traveling to zoos to collect samples to characterize wildlife reproductive biology. Increasing the knowledge of basic reproductive processes and the evolutionary biology of these traits has been one of Rachel’s interests throughout her career.

With the training and education she received from the partnership between George Mason and the Smithsonian’s National Zoo, she began Lincoln Park Zoo’s endocrinology program. Rachel says, “The motto of our program is, ‘If it defecates, we will study it!’” The mission of her program is to promote better scientific understanding of the basic biology of wildlife, including evolutionary and ecological processes, and gain knowledge of the relationship among an animal’s physiology (health and reproduction), behavior and environment using non-invasive methods.

Conducting endocrinology in a laboratory is straightforward, but applying this science to in situ wildlife conservation can be difficult. Rachel has overcome some of the logistical nightmare of doing field endocrine research by designing “field-friendly” fecal-hormone methods that stabilize the extracted hormones so they can be stored at ambient temperature and transported safely back to her laboratory at the zoo for analysis. She’s currently applying this method to black rhinoceroses, domestic livestock, African lions, African elephants and African wild dogs. This method has opened the door to research opportunities where they previously couldn’t have existed. Rachel’s goal is to gather information to improve management decision making in wildlife conservation both in situ and ex situ.


Freeman, E.W., J. M. Meyer, J. Bird, J. Addendorf, B. A. Schulte, R. M. Santymire. 2014. Impacts of environmental pressures on the reproductive health of subpopulations of black rhinoceros (Diceros bicornis bicornis) in Addo Elephant National Park, South Africa. Conservation Physiology 2:Doi:10.1093/conphys/cot034.

Freeman, E.W., J. M. Meyer, J. Addendorf, B. A. Schulte, R. M. Santymire.  2014. Age and fecal gonadal metabolite concentrations affect scraping behavior of black rhinoceros (Diceros bicornis bicornis) in Addo Elephant National Park, South Africa. Journal of Mammalogy 95:340-348.

Jacobs RM, Ross SR, Wagner KE, Leahy M, Meiers ST, Santymire RM 2014. Evaluating the physiological and behavioral response of a male and female gorilla (Gorilla gorilla gorilla) during an introduction. Zoo Biology, 33(5), 394–402.

Reichert-Stewart, J., R. M. Santymire, D. Armstrong, T. M. Harrison and J. R. Herrick. 2014. Fecal endocrine monitoring of reproduction in female snow leopards (Uncia uncia). Theriogenology 82:17-26.

Markham, A.C., R.M. Santymire, E.V. Lonsdorf, M.R. Heintz, I. Lipende, and C.M. Murray.  2014. Rank Effects on Social Stress in Lactating Chimpanzees. Animal Behaviour 87:195-202.

Santymire, R.M., H. Branvold-Faber and P.E. Marinari. 2014. Recovery of the Black-Footed Ferret. In: Biology and Diseases of the Ferret 3rd Edition (J.G. Fox and R.P. Marini, eds.). John Wiley and Sons, Inc.: 219-231.

Hunt, V., Magle, S., Vargas, C., Brown, A., Lonsdorf, E., Sacerdote, A., Sorley, E., Santymire, R. 2014. Survival, abundance, and capture rate of eastern cottontail rabbits in an urban park. Urban Ecosystems 17(2): 547-560.

Daudi, M., R. Santymire, F. Lankester and J. Buza. 2014. The impact of malignant catarrhal fever virus challenge on physiological stress in cattle. American Journal of Research Communication 2(3):13-29.

Rafacz, M. and R. Santymire. 2014. Using odor cues to elicit a behavioral and hormonal response in zoo-housed African wild dogs. Zoo Biology 33:144-149.

Schell, C.J., Young, J.K., Lonsdorf, E.V., Santymire, R.M. 2013. Anthropogenic and physiologically induced stress responses in captive coyotes. Journal of Mammalogy, 94(5):1131–1140.

Rafacz, M., Margulis, S., Santymire, R. 2013. Hormonal and behavioral patterns of reproduction in female hylobatids. Animal Reproduction Science 137(1-2): 103-112.

Armstrong, D. and Santymire, R.M. 2013. Hormonal and behavioral variation in pied tamarins housed in different management conditions. Zoo Biology 32(3): 299-306.

Howell-Stephens, J., Bernier, D., Brown, J., Mulkerin, D., Sanytmire, R.M. 2013. Using non-invasive methods to characterize gonadal hormonal patterns of southern three-banded armadillos (Tolypeutes matacus) housed in North Americans zoo. Animal Reproduction Science 138:314-323.

Murray, C.M., Heintz, M.R., Lonsdorf, E.V., Parr, L.A. and Santymire, R.M. 2013. Validation of a field technique and characterization of fecal glucocorticoid metabolite analysis in wild chimpanzees (Pan troglodytes). American Journal of Primatology 75(1):57-64.

Ganswindt, A., Brown, J., Freeman, E., Kouba, A., Penfold, L., Santymire, R., Vick, M., Wielebnowski, N., Willis, E. and Milnes, M. 2012. . International Society for Wildlife Endocrinology: the future of endocrine measures for reproductive science, animal welfare, and conservation biology. Biology Letters. doi: 10.1098/rsbl.2011.1181.

Santymire, R.,  E.W. Freeman, E. Lonsdorf, M. Heintz, and D. Armstrong. 2012. Assessment of adrenocortical activity after ACTH challenge in diverse African wildlife species. International Journal of Animal and Veterinary Advances 4(2): 99-108.

Howell-Stephens, J., Bernier, D., Brown, J., Mulkerin, D., and Santymire, R.M. 2012. Characterizing adrenocortical activity in zoo-housed southern three-banded armadillos (Tolypeutes matacus). General and Comparative Endocrinology 178(1): 64-74.

Santymire, R.M., Meyer, J., and Freeman, E.W. 2012. Characterizing Sleep Behavior of the Wild Black Rhinoceros (Diceros bicornis bicornis). Sleep 35(11):1569-1574.

Adkin, A., D. Bernier and R.M. Santymire. 2012. Characterizing the reproductive biology and behavior of the zoo-housed Sichuan takin (Budorcas taxicolor tibetana) using non-invasive techniques. Theriogenology 78: 483-494.

Rafacz, M., S. Margulis, and R. Santymire. 2012. Hormonal Correlates of Paternal Care in Three Hylobatid Species. American Journal of Primatology 74(3): 247-260.

Santymire, R.M., S.M. Wisely, T.M. Livieri and J.G. Howard. 2012. Using canine width to determine age in the black-footed ferret Mustela nigripes.. Small Carnivore Conservation 46:17-21, June Issue.

Melber, L., R.M. Santymire, and R. Bergren. 2011. Beyond Borders: Zoo as Training Location for Wildlife Biologists. Journal of Museum Education 36(1): 29-43..

Poessel, S. D. Biggins, R. Santymire, T. Livieri, K. Cooks and L. Angeloni. 2011. Environmental enrichment affects adrenocortical stress responses in the endangered black-footed ferret. General and Comparative Endocrinology 172:526-533.

Loeding, E., D. Bernier, J. Thomas and R.M. Santymire. 2011. Investigating the impacts of a female to female introduction on hormone levels in the sable antelope (Hippotragus niger). Journal of Applied Animal Welfare Science 14: 220-246.

Santymire, R.M., J.L. Brown, R.C. Santymire, R.A. Bauer, D.E. Wildt, J.G. Howard. Online. 2011. Reproductive gonadal activity in the fishing cat (Prionailurus viverrinus) assessed by fecal steroid analyses. Animal Reproduction Science.

Fuller, G., S.W. Margulis, and R.Santymire. 2011. The effectiveness of indigestible markers for identifying individual animal feces and their prevalence of use in North American zoos. Zoo Biology 30(4):379-398.

Heintz, M.R., Santymire, R.M., Parr, L.A., Lonsdorf, E.V. 2011. Validation of cortisol enzyme immunoassay and characterization of salivary cortisol circadian rhythm in chimpanzees (Pan troglodytes). American Journal of Primatology, 73: 1-6.

Santymire, R.M., Fa, J.E., Funk, S.M., O'Connell, D. 2011. Zoo Conservation Biology. Zoo Biology 31(1): 117-118.

Santymire, R.M., and Armstrong, D. 2010. Development of a field-friendly technique for fecal steroid extraction and storage using the African wild dog (Lycaon pictus). Zoo Biology, 28, 1-14.

Rafacz, M., Margulis, S., and Santymire, R. 2009. Comparing the role of androgens in paternal care between gibbon species. Gibbon Journal 5: 74-80.

Wisely, S.M., Howard, J.G., Williams, S.A., Bain, O., Santymire, R.M., Bardsley, K.D., and Williams, E.S. 2008. An unidentified filarial species and its impact on fitness in wild populations of the black-footed ferret (Mustela nigripes). Journal of Wildlife Diseases 44(1):53-64.

Wisely, S.M., Santymire, R.M., Livieri, T.M., Mueting, S.A., Wildt, D.E., and Howard, J.G. 2008. Genotypic and phenotypic consequences of reintroduction history: case study of the black-footed ferret. Conservation Genetics 9(2):389-399.

Santymire, R.M., P.E. Marinari, J.S. Kreeger, D.E. Wildt and J.G. Howard. 2007. Slow Cooling Prevents Cold-Induced Damage to Sperm Motility and Acrosomal Integrity in the Black-Footed Ferret (Mustela nigripes). Reproduction, Fertility and Development 19:652-663.

Pukazhenthi, B., R. Santymire, A. Crosier, J.G. Howard, D. E. Wildt. 2006. Challenges in cryopreserving endangered mammal spermatozoa: morphology and the value of acrosomal integrity as markers of cryo-survival. Spermatology. Soc Reprod Fertil Suppl, Nottingham: Nottingham Press, 65:433-446.

Santymire, R.M., Marinari, P.E., Kreeger, J.S., Wildt, D.E., and Howard, J.G.  2006. Determining semen osmolality and effect of medium osmolality on sperm viability in the black-footed ferret (Mustela nigripes). Cryobiology 54:37-50.

Howard, J.G., R.M. Santymire, P.E. Marinari, J.S. Kreeger, L. Williamson and D.E. Wildt. 2006. Use of reproductive technology for black-footed ferret recovery. In: Recovery of the Black-Footed Ferret: Progress and Continuing Challenges (Eds., J.E. Roelle, B.J. Miller, J.L. Godbey and D.E. Biggins.). pp. 28-36. U.S. Geological Survey Scientific Investigations Report 2005-5293, Reston, VA.

Wisely, S.M., Santymire, R.M., Livieri, T.M., Marinari, P.E., Kreeger, J.S., Wildt, D.E. and Howard, J.G. 2005. Environment influences morphology and development for in situ and ex situ populations of the black-footed ferret (Mustela nigripes). Animal Conservation, 8: 321-328.

Brown, J.L., Goritz, F., Pratt-Hawkes, N. Hermes, R., Galloway, M., Graham, L.H., Gray, C., Walker, S.L., Gomez, A., Moreland, R., Murray, S., Schmitt, D.L., Howard, J.G., Lehnhardt, J., Beck, B., Bellem, A., Montali, R. and Hildebrandt, T.B. 2004. Successful artificial insemination of an Asian elephant at the National Zoological Park. Zoo Biology, 23: 45-63.

Terio, K.A., Brown, J.L., Moreland, R. and Munson, L. 2002. Comparison of different drying and storage methods on quantifiable concentrations of fecal steroids in the cheetah. Zoo Biology, 21: 215-222.

Moreland, R.B., Richardson, M.E., Lamberski, N. and Long, J.A. 2001. Characterizing the reproductive physiology of the male southern black howler monkey, Alouatta caraya. Journal of Andrology, 22(3): 395-403.