Dr. Peter J. Fashing

Before joining the faculty at Cal State Fullerton, I was a Research Scientist with the Pittsburgh Zoo. I have conducted conservation and research projects in several sub-Saharan African countries, including Kenya, Rwanda, and Ethiopia. I grew up in Williamsburg, VA and earned my Bachelor’s degree in Anthropology and Biology at the College of William and Mary. In 1999, I earned my Ph.D. in Anthropology from Columbia University, where I studied under Dr. Marina Cords, a leading expert in forest monkey behavior and ecology. Dr. Cords oversees one of the longest running field projects on forest monkeys in Africa, at Kakamega Forest, Kenya. For my Ph.D., I lived in a rustic cabin on the edge of the Kakamega Forest for a year and a half studying (a) the ecological determinants of feeding and ranging behavior in eastern black and white colobus monkeys (Colobus guereza) and (b) the strategies adopted by male and female colobus during encounters between groups. After earning my Ph.D., I completed a one-year postdoctoral fellowship with the Wildlife Conservation Society (WCS). At WCS, I conducted a study of the costs and benefits of group life for another colobus monkey species (Angolan colobus or Colobus angolensis) that forms unusually large groups of over 300 members in Rwanda's Nyungwe Forest - one of the largest remaining montane rainforests in Africa. After completing my post-doc, I taught at Columbia University, Queens College, and Seton Hall University before becoming a Research Scientist with the Pittsburgh Zoo in 2002. During my six years at the Pittsburgh Zoo, I expanded my research program at Kakamega, Kenya and, in 2005, established a new research site at Guassa, Ethiopia, where with Dr. Nga Nguyen, I co-direct the Guassa Gelada Research Project Opens in new window , a longitudinal study of the behavioral ecology and conservation biology of the gelada monkey (Theropithe cus gelada).


Teaching Interests

I primarily teach courses in the Evolutionary Anthropology wing of the Anthropology Department, including ANTH 101: Introduction to Biological Anthropology, ANTH 301: Primate Behavior, and ANTH 457: Advanced Primate Behavior, ANTH 454: Primate Conservation. I also regularly teach courses in the Environmental Studies (ENST 500: Environmental Issues and Approaches) and Honors (HONR 301T: Globalization and the Environment) programs.I also regularly teach the introductory core course (ENST 500: Environmental Issues and Approaches) in the Environmental Studies Master’s (M.S.) Program.


Research Interests 

My research focuses on the behavioral ecology and conservation biology of the living primates. Nonhuman primates are excellent models of human behavior and evolution because of their social, ecological, and behavioral similarity to humans. Much of my research examines two inter-related areas of primate ecology and conservation biology: (1) the costs and benefits of group living for male and female primates, and (2) the influence of resource abundance and distribution on the feeding and ranging ecology of primates. My past and present research focuses on wild populations of monkeys in East Africa, including Kenya, Rwanda and Ethiopia. By studying nonhuman primates in their natural settings, I can monitor the interactions between behavior and ecology within the selective environments in which these interactions evolved. My research aims to shed new light on the biological processes that shape the behavior and ecology of humans and other animals.   

Currently, I am investigating the behavioral ecology and conservation biology of the rare and enigmatic gelada monkey (Theropithecus gelada) at a remote field site in northern Ethiopia called Guassa (for more information, visit the Guassa Gelada Research Project website Opens in new window  and see the recent photoessay on geladas and Guassa in the April 2017 issue of National Geographic magazine). Guassa is an unusually ecologically pristine alpine grassland that has been conserved by one of the few surviving ancient indigenous conservation initiatives on the African continent. My current research at Guassa focuses on gelada feeding and nutritional ecology and what it can tell us about theropith and hominin dietary evolution. I am also part of a large collaborative project with other American, Ethiopian, German, and Norwegian scientists to determine the distribution and abundance of geladas across the Ethiopian Highlands. This project will help identify the conservation threats facing geladas and how they can be mitigated. I welcome student participation and collaboration on my research in primate behavioral ecology and conservation biology. 



  • Trosvik P., de Muinck E.J., Rueness E.K., Fashing P.J., Beierschmitt E.C., Callingham K.R., Kraus J.B., Trew T.H., Moges A., Mekonnen A., Venkataraman V.V., Nguyen N. 2018. Multilevel social structure and diet shape the gut microbiota of the gelada monkey, the only grazing primate. Microbiome 6: 84. DOI 10.1186/s40168-018-0468-6
  • Gutema, T.M., Atickem, A., Bekele, A., Sillero-Zubiri, C., Kasso, M., Tsegaye, D., Venkataraman, V.V., Fashing, P.J., Zinner, D., and Stenseth, N.C. (2018). Competition between sympatric wolf taxa: An example involving African and Ethiopian wolves. Royal Society Open Access DOI: 10.1098/rsos.172207
  • Mekonnen, A., Fashing, P.J., Sargis, E.J., Venkataraman, V.V., Bekele, A., Hernandez-Aguilar, A., Rueness, E.K., and Stenseth, N.C. (2018). Flexibility in positional behavior, strata use, and substrate utilization among Bale monkeys (Chlorocebus djamdjamensis) in response to habitat fragmentation and degradation. American Journal of Primatology DOI: 10.1002/ajp.22760
  • Mekonnen, A., Fashing, P.J., Bekele, A., Hernandez-Aguilar, R.A., Rueness, E.K., and Stenseth, N.C. (2018). Impacts of habitat loss and fragmentation on the feeding ecology of Bale monkeys (Chlorocebus djamdjamensis) in the southern Ethiopian Highlands. BMC Ecology DOI: 10.1186/s12898-018-0161-4
  • Abu, K., Mekonnen, A., Bekele, A., and Fashing, P.J. (2018). Diet and activity patterns of Arsi geladas in low-elevation disturbed habitat south of the Rift Valley at Indetu, Ethiopia. Primates 59: 153-161.DOI: 10.1007/s10329-017-0640-9
  • Nguyen, N., Lee, L.M., Fashing, P.J., Nurmi, N.O., Stewart, K.M., Turner, T.J., Barry, T.S., Callingham, K.R., Goodale, C.B., Kellogg, B.S., Burke, R.J., Bechtold, E.K., Claase, M.J., Eriksen, G.A., Jones, S.C.Z., Kerby, J.T., Kraus, J.B., Miller, C.M., Trew, T.H., Zhao, Y., Beierschmitt, E.C., Ramsay, M.S., Reynolds, J.D., and Venkataraman, V.V. (2017). Comparative primate obstetrics: Observations of 15 diurnal births in wild gelada monkeys (Theropithecus gelada) and their implications for understanding human and nonhuman primate birth evolution. American Journal of Physical Anthropology 163: 14-29. (NPR: A new view into the primate birthing process)
  • Mekonnen, A., Fashing, P.J., Bekele, A., Hernandez-Aguilar, R.A., Rueness, E.K., Nguyen, N., and Stenseth, N.C. (2017). Impacts of habitat loss and fragmentation on the activity budget, ranging ecology and habitat use of Bale monkeys (Chlorocebus djamdjamensis) in the southern Ethiopian Highlands.  American Journal of Primatology DOI: 10.1002/ajp.22644.
  • Fashing, N.J., Ueckermann, E.A., Fashing, P.J., Nguyen, N., Back, A.M., and Allison, L.A. (2016). Bryobia abyssiniae (Prostigmata: Tetranychidae), a new species from the highlands of Ethiopia. International Journal of Acarology 42: 366-376.
  • Fashing, P.J. (2016). Colobus angolensis. In: N. Rowe and M. Myers (eds.). All the World’s Primates. East Hampton, NY: Pogonias Press, pp. 522-523.
  • Fashing, P.J. (2016). Colobus guereza. In: N. Rowe and M. Myers (eds.). All the World’s Primates. East Hampton, NY: Pogonias Press, pp. 524-526.
  • Fashing, P.J. and Nguyen, N. (2016). Theropithecus gelada. In: N. Rowe and M. Myers (eds.). All the World’s Primates. East Hampton, NY: Pogonias Press, pp. 447-449.
  • Shapiro, A.E., Venkataraman, V.V., Nguyen, N., and Fashing, P.J. (2016). Dietary ecology of fossil Theropithecus: Inferences from dental microwear textures of extant geladas from ecologically diverse sites. Journal of Human Evolution 99: 1-9.
  • Nguyen, N., Fashing, P.J., Boyd, D.A., Barry, T.S., Burke, R.J., Goodale, C.B., Jones, S.C.Z., Kerby, J.T., Kellogg, B.S., Lee, L.M., Miller, C.M., Nurmi, N.O., Ramsay, M.S., Reynolds, J.D., Stewart, K.M., Turner, T.J., Venkataraman, V.V., Knauf, Y., Roos, C. and Knauf, S. (2015). Fitness impacts of tapeworm parasitism on wild gelada monkeys at Guassa, Ethiopia. American Journal of Primatology 77: 579-594.
  • Venkataraman, V.V., Kerby, J.T., Nguyen, N. Ashenafi, Z., and Fashing, P.J. (2015). Solitary Ethiopian wolves increase predation success on rodents when among grazing gelada monkey herds. Journal of Mammalogy 96: 129-137. (New Scientist: Monkeys’ cosy alliance with dogs looks like domestication)
  • Fashing, P.J., Nguyen, N., Venkataraman, V.V., and Kerby, J.T. (2014). Gelada feeding ecology in an intact ecosystem at Guassa, Ethiopia: Variability over time and implications for theropith and hominin dietary evolution. American Journal of Physical Anthropology 155(1): 1-16.
  • Venkataraman, V.V., Glowacka, H., Fritz, J., Clauss, M., Seyoum, C., Nguyen, N., and Fashing, P.J. (2014). Effects of dietary fracture toughness and dental wear on chewing efficiency in geladas (Theropithecus gelada). American Journal of Physical Anthropology 155(1): 17-32.
  • Fashing, P.J. and Oates, J.F. (2013). Colobus guereza. In: J. Kingdon, D. Happold, and T. Butynski (eds.). Mammals of Africa. London: Bloomsbury Publishing, pp. 111-119.
  • Tesfaye, D., Fashing, P.J., Bekele, A., Mekonnen, A., and Atickem, A. (2013). Ecological flexibility in Boutourlini’s blue monkey (Cercopithecus mitis boutourlini) in Jibat Forest, Ethiopia: A comparison of habitat use, ranging behavior, and diet in intact and fragmented forest. International Journal of Primatology 34: 615-640. (PDF PDF File )
  • Fashing, P.J.,Nguyen, N., Luteshi, P., Opondo, W., Cash, J.F., and Cords, M. (2012). Evaluating the suitability of planted forests for African forest monkeys: A case study from Kakamega Forest, Kenya. American Journal of Primatology 74: 77-90. (PDF PDF File )
  • Laurance, W.F. et al. (many authors including Fashing, P.J.). (2012). Averting biodiversity collapse in tropical forest protected areas. Nature 489:290-294. (Science Daily: Can nature parks save biodiversity? Opens in new window )
  • Mekonnen, A., Bekele, A., Fashing, P.J., Lernould, J.M., Atickem, A., and Stenseth, N.C. (2012). Newly discovered Bale monkey populations in forest fragments in southern Ethiopia: Evidence of crop raiding, hybridization with grivets, and other conservation threats. American Journal of Primatology 74: 423-432. (PDF PDF File )
  • Fashing, P.J. (2011). African colobine monkeys: Their behavior, ecology, and conservation. In: C. Campbell, A. Fuentes, K. MacKinnon, S. Bearder, and R. Stumpf (eds.). Primates in Perspective. Oxford: Oxford University Press, 2nd edition, pp. 203-229.
  • Fashing, P.J. and Nguyen, N. (2011). Behavior towards the dying, diseased, and disabled among animals and its relevance to paleopathology. International Journal of Paleopathology 1: 127-128. (PDF PDF File )
  • Fashing, P.J., Nguyen, N., Barry, T.S., Goodale, C.B., Burke, R.J., Jones, S.C.Z., Kerby, J.T., Lee, L.M., Nurmi, N.O., Venkataraman, V.V. (2011). Death among geladas (Theropithecus gelada):A broader perspective on mummified infants and primate thanatology. American Journal of Primatology73: 405-409. (PDF PDF File ) (New Scientist: Bereaved animals grieve – if their lifestyle allows it Opens in new window )
  • Fashing, P.J., Nguyen, N., and Fashing, N.J. (2010). Behavior of geladas and other endemic wildlife during a desert locust outbreak at Guassa, Ethiopia: Ecological and conservation implications. Primates 51: 193-197. (PDF PDF File )(CBC Quirks & Quarks: Monkeys munch on locust lunch Opens in new window )
  • Mekonnen, A., Bekele, A., Fashing, P.J., Hemson, G., and Atickem, A. (2010). Diet, activity patterns, and ranging ecology of the Bale monkey (Chlorocebus djamdjamensis) in Odobullu Forest, Ethiopia. International Journal of Primatology 31: 339-362. (PDF PDF File ) (BBC Earth News Opens in new window )
  • Fashing, P.J. (2007). African colobine monkeys: Patterns of between-group interaction. In: C. Campbell, A. Fuentes, K. MacKinnon, M. Panger, and S. Bearder (eds.). Primates in Perspective. Oxford: Oxford University Press, 1st edition, pp. 201-224.
  • Fashing, P.J. (2007). Behavior, ecology, and conservation of colobine monkeys: An introduction. International Journal of Primatology 28: 507-511. (PDF PDF File )
  • Fashing, P.J., Dierenfeld, E.S., and Mowry, C.B. (2007). Influence of plant and soil chemistry on food selection, ranging patterns, and biomass of Colobus guereza in Kakamega Forest, Kenya. International Journal of Primatology 28: 673-703. (PDF PDF File )
  • Fashing, P.J., Mulindahabi, F., Gakima, J.-B., Masozera, M., Mununura, I., Plumptre, A.J., and Nguyen, N. (2007). Activity and ranging patterns of Angolan colobus (Colobus angolensis ruwenzorii) in Nyungwe Forest, Rwanda: Possible costs of large group size. International Journal of Primatology 28: 529-550. (PDF PDF File )
  • Harris, T.R., Fitch, W.T., Goldstein, L.M., and Fashing, P.J. (2006). Black and white colobus monkey (Colobus guereza) roars as a source of both honest and exaggerated information about body mass. Ethology 112: 911-920. (PDF PDF File )
  • Fashing, P.J. (2004). Mortality trends in the African cherry (Prunus africana) and the implications for colobus monkeys (Colobus guereza) in Kakamega Forest, Kenya. Biological Conservation 120(4): 449-459. (PDF PDF File )
  • Fashing, P.J., Forrestel, A., Scully, C., and Cords, M. (2004). Long-term tree population dynamics and their implications for the conservation of the Kakamega Forest, Kenya. Biodiversity and Conservation13(4): 753-771. (PDF PDF File )
  • Fashing, P.J. and Gathua, J.M. (2004). Spatial variation in the structure and composition of an East African rain forest. African Journal of Ecology 42(3): 189-197.(PDF PDF File )
  • Fashing, P.J. (2002). Population status of black and white colobus monkeys (Colobus guereza) in Kakamega Forest, Kenya: Are they really on the decline? African Zoology 37(2): 119-126. (PDF PDF File )
  • Plumptre, A.J., Masozera, M., Fashing, P.J., McNeilage, A., Ewango, C., Kaplin, B., and Liengola, I. (2002). Biodiversity surveys of the Nyungwe Forest Reserve in S.W. Rwanda. WCS Working Paper No. 19, New York: Wildlife Conservation Society. Pp. 1-96. (PDF PDF File )
  • Fashing, P.J. (2001a). Activity and ranging patterns of guerezas in the Kakamega Forest: Intergroup variation and implications for intragroup feeding competition. International Journal of Primatology 22(4): 549-577. (PDF PDF File )
  • Fashing, P.J. (2001b). Feeding ecology of guerezas in the Kakamega Forest: The importance of Moraceae fruit in their diet. International Journal of Primatology 22(4): 579-609. (PDF PDF File )
  • Fashing, P.J. (2001c). Male and female strategies during intergroup encounters in guerezas (Colobus guereza): Evidence for resource defense mediated through males and a comparison with other primates. Behavioral Ecology and Sociobiology 50(3): 219-230. (PDF PDF File )
  • Fashing, P.J. and Cords, M. (2000). Diurnal primate densities and biomass in the Kakamega Forest: An evaluation of census methods and a comparison with other forests. American Journal of Primatology50(2): 139-152. (PDF PDF File )
  • Sterling, E. J., Nguyen, N., and Fashing, P.J. (2000). Spatial patterning in nocturnal prosimians: A review of methods and relevance to studies of sociality. American Journal of Primatology 51(1): 3-19. (PDF PDF File )


Popular Articles

  • Fashing, P. and Nguyen, N. (2015). Life on the roof of Africa: Our quest to study the gelada monkey. ZOONOOZ January: 22-23.
  • Fashing, P. (2007). The modern zoo: Ensuring a future for wildlife and wild places. Zoo Explorer 11: 14-19.
  • Fashing, P. (2006/2007). Expedition to the baboons at the top of the world. Zoo Explorer 10: 18-20. 
  • Fashing, P. (2006). Animal friends. Pittsburgh Post-Gazette June 16. 
  • Fashing, P. (2005). Notes from the rainforest: A field season in Kenya. Zoo Explorer 8: 16-18. 
  • Fashing, P. (2004). Into Africa: Encounters with the future of conservation. Zoo Explorer 7: 6, 16-17.
  • Cords, M. and Fashing, P. (2002). Conserving Africa’s forests. CERC Notes Fall 2002: 11. 
  • Fashing, P. (1999). Forest guardian. Swara 22: 18-23.


Book Reviews

  • Fashing, P.J. (2001). Egalitarianism and group selection in human evolution. Review of C. Boehm’s Hierarchy in the Forest: The Evolution of Egalitarian Behavior. Current Anthropology 42(5): 770-771.(PDF) PDF File  
  • Fashing, P. (2001). An introduction to primate behavioral ecology suitable for college students? Review of K.B. Strier’s Primate Behavioral Ecology. American Journal of Primatology 53(4): 177-178. (PDF) PDF File



Fashing, P.J. (1999). The Behavioral Ecology of an African Colobine Monkey: Diet, Range Use, and Patterns of Intergroup Aggression in Eastern Black and White Colobus Monkeys (Colobus guereza).Columbia University: New York, NY. Supervised by Dr. Marina Cords.


Contact Information

Mailing Address:
Department of Anthropology
McCarthy Hall 426
California State University Fullerton
Fullerton, CA 92834
Office: McCarthy Hall 422A
Phone: (714) 278-3977
E-mail:  pfashing@fullerton.edu

A view out over the Kakamega Forest