College of Liberal and Fine Arts

Michael Muehlenbein, PhD, MsPH


Department of Anthropology

Research area: Biological Anthropology


Phone: (210) 458-6413

Office: MH 4.03.44 / Laboratory: SRL 1.134

Research in Progress

Infectious diseases and hormones underpin all aspects of my primary, long-term research agenda. I have maintained both field- and laboratory-based research projects, with independent ventures in behavioral endocrinology and infectious disease ecology, but with a predominant campaign in evolutionary endocrinology and ecological immunology. These projects/ideas have built upon one another in an effort to identify logical direction in research on fundamental questions regarding the physiologies and behaviors of humans, monkeys and apes, with particular focus on explicating the proximate and ultimate causes and consequences of immune-endocrine interactions.

I utilize quantitative methods from endocrinology and immunology to test predictions derived from evolutionary theory about the physiologies and behaviors of humans, monkeys and apes. I have aimed to understand the interactions between the reproductive endocrine and immune systems, the physiological and ecological determinants of variation in reproductive and immune functions, and ultimately the fitness consequences of this variation. Driven by a dearth of information on hormone-mediated immunity in humans, monkeys and apes relative to other species, I was drawn to the following research questions: 1) how and why do hormones mediate immune responses to infectious diseases in males, 2) how and why do hormone levels change in response to immune activation, and 3) how are reproductive and immune functions involved in male life history trade-offs? My focus has been primarily on testosterone, which is hypothesized to suppress immune functions. But how does it do this, and under what host conditions? Does having higher testosterone really increase susceptibility to infectious diseases, and how/why do testosterone levels change in response to illness in a human, monkey or ape host? These ‘why’ questions come from evolutionary theory: ‘why’ should such relationships exist? The ‘how’ questions are enabled through the application of endocrinological and immunological methods.

Current projects involve quantifying the energetic costs of immune responses in both men and women, and analyzing the immunomodulatory actions of a number of other hormones (primarily estradiol, dehydroepiandrosterone, and oxytocin). Because hormones influence and regulate immune, metabolic and reproductive functions, identifying the complex interactions between hormones and immune factors will have an important impact on understanding the optimization of hormonal activity under varying environmental conditions, and consequently the evolution of the life history trade-offs between endocrine and immune functions.

My most recent NSF-funded project focuses on a nonhuman primate model to address better the roles of immunocompetence in sexual selection for condition-dependent signals of fitness. Such a project also affords me the opportunity to continue to develop non-invasive, functional measures of immunity that can be applied to human and nonhuman primate research under a variety of field conditions. Finally, I maintain active international fieldwork in conservation medicine, an applied aspect of my research agenda to identify zoonotic sources of human malaria infection from monkeys and apes, and to understand the complex motivations and environmental values that influence human desire (biophilia) for contact with wild primates. This latter project specifically involves a cross-cultural analysis of personality, biodiversity awareness, and risks of disease transmission associated with primate-based tourism. Diverse training has facilitated such diverse projects, but a grounding in biological anthropology focuses my model organisms on humans, monkeys and apes – from theoretical and empirical work on the evolution of physiologies and behaviors in these species, to applied research on human-borne diseases transmitted to wild primates.

Find more at Dr. Muehlenbein's website.


Ph.D., Yale University, 2004
MsPH, Tulane University, 2000


As an educator, my goal is to help students develop a conceptual framework for independent, critical thought. I try to do this by communicating the fundamental concepts of different subjects in an enjoyable manner that promotes active retention of information and the application of concepts and processes. I believe the best way to nurture good critical thinking practices is to be encouraging, empathetic, flexible, fair-minded and respectful to students, to treat them as junior colleagues when possible/practical, to establish clear expectations of them at all times, and to support their respectful inquisition and analysis of others’ research. It is critical to motivate students using realistic examples of general principles applied to current events, to show them examples of good science and how to replicate it, to cultivate written and oral presentation skills, to support the development of argumentation skills, all while providing them with cognitive autonomy. I accomplish this most effectively by creating a relaxed learning atmosphere.

Prospective Students: I am accepting graduate students interested in a variety of topics, including (but not limited to):

1. One Health / Conservation Medicine, including primate infectious disease ecology, human-wildlife interactions and emerging infectious diseases, travel medicine and ecotourism.

2. Behavioral endocrinology, particularly as it relates to animal stress physiology and environmental change, the evolution of sickness behaviors, and the effects of early developmental exposures on adult behaviors and biology.

3. Evolutionary medicine, specifically hormone-mediated immune functions (estrogens and oxytocin in particular).

Recent Publications


2015 – Muehlenbein, MP, ed. Basics in Human Evolution. New York: Elsevier Academic Press.

2010 – Muehlenbein, MP, ed. Human Evolutionary Biology. Cambridge: Cambridge University Press.


Sample of Chapters

2014 - Muehlenbein MP, Wallis J. Understanding risks of disease transmission associated with primate-based tourism. In: Russon A, Wallis J, eds. Primate-Focused Tourism. Cambridge University Press, p. 278-291.

2013 - Muehlenbein MP, Lewis CM. Health assessment and epidemiology. In: Sterling, Bynum and Blair, eds. Primate Ecology and Conservation: A Handbook of Techniques. Oxford University Press, p. 40-57.

2012 - Muehlenbein MP. Emerging infectious diseases and human-wildlife interactions. In: Brondizio and Moran, eds. Human-Environment Interactions. Springer, p. 79-94.

2011 - Muehlenbein MP, Flinn MV. Patterns and processes of human life history evolution. In: Flatt and Heyland, eds. Mechanisms of Life History Evolution. Oxford University Press, p. 153-168.

2010 - Muehlenbein MP. Evolutionary medicine, immunity and infectious diseases. In: Muehlenbein, ed. Human Evolutionary Biology. Cambridge University Press, p. 459-490.

2009 - Muehlenbein MP. The application of endocrine measures in primate parasite ecology. In: Huffman and Chapman, eds. Primate Parasite Ecology: The Dynamics of Host-Parasite Relationships. Cambridge University Press, p. 63-81.


Sample of Articles

2017 - Muehlenbein MP. Primates on display: Potential disease consequences beyond bushmeat. Yearbook of Physical Anthropology 162:32-43. 

2016 - Muehlenbein MP. Disease and human-animal interactions. Annual Review of Anthropology 45:395-416.

2016 - Shattuck EC, Muehlenbein MP. Towards an integrative picture of human sickness behavior. Brain, Behavior, and Immunity 57:255-262.

2015 - Muehlenbein MP, Delgado MP, Prall SP, Ambu L, Nathan S, Alsisto S, Ramirez D, Selgado M, Escalante A. Evolutionary relationships among malaria (Plasmodium) species in nonhuman primates of Borneo. Molecular Biology and Evolution 32:422-439.

2015 - Brenner S, Jones JP, Rutanen Whaley RH, Parker W, Flinn M, Muehlenbein MP. Evolutionary mismatch and chronic psychological stress. Journal of Evolutionary Medicine 3:235885.

2015 - Shattuck EC, Muehlenbein MP. Human sickness behavior: Ultimate and proximate explanations. American Journal of Physical Anthropology DOI: 10.1002/ajpa.22698.

2015 - Georgiev A, Muehlenbein MP, Prall SP, Emory Thompson M, Maestripieri D. Male quality, dominance rank and mating success in free-ranging rhesus macaques. 
Behavioral Ecology 26(3)763-772.

2015 - Shattuck E, Muehlenbein MP. Mood, behavior, testosterone, cortisol, and interleukin-6 in adults during immune activation: A pilot study to assess sickness behaviors in humans. American Journal of Human Biology 27:133-135.

2014 - Prall SP, Muehlenbein MP. Testosterone and immune function in primates: A brief summary with methodological considerations. International Journal of Primatology 35:805-824.

2012 - Flinn MV, Ponzi D, Muehlenbein MP. Hormonal mechanisms for regulation of aggression in human coalitions. Human Nature 23:68-88.

2012 - Muehlenbein MP, Ancrenaz M, Sakong R, Ambu L, Prall SP, Fuller G, Raghanti MA. Ape conservation physiology: Fecal glucocorticoid responses in wild Pongo pygmaeus morio following human visitation. PLoS ONE 7(3): e33357.

2011 - Demas GE, Zysling DA, Beecher B, Muehlenbein MP, French SS. Beyond phytohemagglutination: Assessment of vertebrate immune function across ecological contexts. Journal of Animal Ecology 80:710-730.

2010 - Muehlenbein MP, Martinez LA, Lemke AA, Ambu L, Nathan S, Alsisto S, Sakong R. Unhealthy travelers present challenges to sustainable ecotourism. Travel Medicine and Infectious Disease 8:169-175.

2010 - Muehlenbein MP, Hirschtick JL, Bonner JZ, Swartz AM. Towards quantifying the usage costs of human immunity: Altered metabolic rates and hormone levels during acute immune activation in men. American Journal of Human Biology 22:546-556.

2010 - Muehlenbein MP, Watts DP. The costs of dominance: Testosterone, cortisol and intestinal parasites in wild male chimpanzees. BioPsychoSocial Medicine 4:21.

2009 - Muehlenbein MP, Ancrenaz M. Minimizing pathogen transmission at primate ecotourism destinations: The need for input from travel medicine. Journal of Travel Medicine 16:229-232.

2008 - Muehlenbein MP. Adaptive variation in testosterone levels in response to immune activation: Empirical and theoretical perspectives. Social Biology 53:13-23.

2008 - Muehlenbein MP, Martinez LA, Lemke AA, Andau P, Ambu L, Nathan S, Alsisto S, Sakong R. Perceived vaccination status in ecotourists and risks of anthropozoonoses. EcoHealth 5:371-378.

2006 - Muehlenbein MP. Intestinal parasite infections and fecal steroid levels in wild chimpanzees. American Journal of Physical Anthropology 130:546-550.

2005 - Muehlenbein MP, Bribiescas RG. Testosterone-mediated immune functions and male life histories. American Journal of Human Biology 17:527-558.

2005 - Muehlenbein MP, Algier J, Cogswell F, James M, Krogstad D. The reproductive endocrine response to Plasmodium vivax infection in Hondurans. American Journal of Tropical Medicine and Hygiene 73:178-187.

2004 - Muehlenbein MP, Watts DP, Whitten P. Dominance rank and fecal testosterone levels in adult male chimpanzees (Pan troglodytes schweinfurthii) at Ngogo, Kibale National Park, Uganda. American Journal of Primatology 64:71-82.


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Department of Anthropology

University of Texas at San Antonio

College of Liberal and Fine Arts

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