Tana River red colobus monkey
Ring-tailed lemur
Tana River red colobus monkey
Eritrean grivet (D. Brahane)
Indri (N. Garbutt)
Diadema’s sifaka (N. Garbutt)
Tana River crested mangabey
black & white colobus monkey (P. Fashing)






I have been studying the ecology of African primates since 1990.  Much of my research is centered on feeding ecology.  What is a particular primate species eating?  What are the costs and benefits to the animal from a nutritive perspective?  What type of digestive specializations, if any, does the animal possess?  What type of habitat does the animal live in?  Is the species and/or its habitat threatened?  Most non-human primates are found in parts of the world where human-induced activities are having a negative impact on their survival.  Therefore, there is usually a conservation component to my work with primates.

     Non-human primates have diverse diets, but most rely on plant parts as their major source of nutrition.  Plants, however, do not necessarily sit passively by and allow themselves to be eaten.  Chemical constituents and physical structures provide protection for the plant, and generally no single plant can provide all of the essential nutrients for an animal, including a primate.  Due to physiological differences, some primates are better able to digest fiber and are adapted to a more folivorous (i.e., leafy) diet, some are more frugivorous (i.e., are fruit eaters), while others depend more upon insects (i.e., are insectivorous).

Primate studies that I have been involved in include:

1)     The Tana River Red Colobus Monkey (Piliocolobus rufomitratus).  Colobus monkeys are unique in that they have a ruminant-like digestive system, which allows them to extract nutrients from fiber-rich foods and to potentially detoxify some harmful plant chemical defenses.  This study was conducted in the forests along the Tana River in southeastern Kenya, home to two of the world’s most endangered primates, the Tana River red colobus monkey and the Tana River crested mangabey (Cercocebus galeritus).

2)     Ring-tailed Lemur (Lemur catta) Nutrition.  I served as the Nutrition Advisor for the ring-tailed lemur Species Survival Plan (SSP).  Ring-tailed lemurs are only found on the island of Madagascar in the Indian Ocean, but there is also a fairly sizeable population in captivity around the world, including several free-ranging groups on St. Catherines Island off the coast of Georgia.

3)     Sympatric Indri (Indri indri) and Diadema’s Sifaka (Propithecus diadema diadema). These are Madagascar’s largest living lemurs and their geographic ranges overlap, meaning that they could potentially compete with one another for resources.  While they do not have specialized stomachs like the colobine monkeys, they do have an enlarged cecum (hindgut) for the retention and processing of high fiber foods.  Dr. Joyce Powzyk (Duke University, Wesleyan University), the project’s principle investigator, and I determined that the indri’s diet is primarily folivorous while the diadema sifaka eats a variety of fruits, seeds, flowers and leaves, thereby allowing these two species to coexist.

4)     An Ecological Study of Eritrean Grivet Monkeys (Cercopitheus aethiops aethiops).  Vervet monkeys are found throughout Africa, but Eritrea, above Ethiopia and just below the Red Sea, appears to harbor the northernmost population.  Distinct morphological differences occur in the Eritrean population (known locally as grivet monkeys), including long white fur at the cheeks, and they have a highly arboreal lifestyle in the dwindling tropical evergreen forests of the Semanawi Bahri region of the country.

5)     Western Lowland Gorilla (Gorilla gorilla gorilla) Diet.  This study was conducted on lowland gorillas living in Bai Hokou, Central African Republic in collaboration with Dr. Melissa Remis (Purdue University), the principle investigator, and Dr. Ellen Dierenfeld.  Despite their large size and fierce portrayal in popular media, gorillas are strictly vegetarians, eating large quantities of fruits and leaves.

6)     Black and White Colobus Monkeys (Colobus guereza) in Kakamega Forest, Kenya.  Dr. Peter Fashing was the principle investigator on this project, and Dr. Ellen Dierenfeld was also involved.  Studies from a number of Paletropical rain forests through the years have shown a positive correlation between the protein/fiber ratio of available foliage (as a measure of food quality) and the biomass of resident colobus monkeys.  Our data from Kakamega fits this pattern.

Relevant Publications:

Ganzhorn, J. U., S. J. Arrigo- Nelson, V. Carrai, M. K. Chalise, G. Donati, I. Droescher, T. M. Eppley, M. T. Irwin, F. Koch, A. Koenig, M. M. Kowalewski, C. B. Mowry, E. R. Patel, C. Pichon, J. Ralison, C. Reisdorff, B., E. Stalenberg, D. Starrs, J. Terboven, P. C. Wright and W. J. Foley (2017) The Importance of Protein in Leaf Selection of Folivorous Primates. American Journal of Primatology 79(4): 1-13.

Fashing, P.J., E.S. Dierenfeld and C. B. Mowry (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(3): 673-703.

Powzyk, J.A. and C.B. Mowry (2006) The feeding ecology and related adaptations of Indri indri. In Gould, L and Sauther, M.S. (eds.) Lemurs: Ecology and Adaptation, Springer, New York, pp. 355 – 370.

Powzyk, J.A. and C.B. Mowry (2003) Diet and feeding differences between sympatric indrids:  Propithecus diadema diadema and Indri indri. International Journal of Primatology 24(6): 1143-1162.

Gaffney, S., V.Williams, P. Flynn, R. Carlino, C. Mowry, E. Dierenfeld, C. Babb, J.Fan, and W.A. Tramontano. (2004) Tannin/polyphenol effects on iron solubilization in vitro. BIOS 75(2): 43-52.

Remis, M.J., E.S. Dierenfeld, C.B. Mowry, and R.W. Carroll (2001) Nutritional aspects of western lowland gorilla (Gorilla gorilla gorilla) diet during seasons of fruit scarcity at Bai Hokou, Central African Republic. International Journal of Primatology 22(5): 807-836.

Mowry, C.B. and J.L. Campbell (2001) Nutrition. In: Ring-tailed lemur (Lemur catta) Husbandry Manual. American Association of Zoos and Aquariums.

Mowry, C.B., C. McCann, R. Lessnau and E. Dierenfeld (1997) Secondary compounds in foods selected by free-ranging primates on St. Catherines Island, GA. Proceedings of the Second Conference of the Nutrition Advisory Group/American Zoo and Aquarium Association on Wildlife Nutrition, Ft.Worth, Texas.

Mowry, C.B., B.S. Decker and D.J. Shure. (1996) The role of phytochemistry in dietary choices of Tana River red colobus monkeys (Procolobus badius rufomitratus). International Journal of Primatology 17: 63-84.  

Mowry, C.B. (1995) Possible infanticidal behaviour by a Tana River red colobus (Procolobus badius rufomitratus). African Primates 1: 48-51.