International Journal of Primatology

, Volume 33, Issue 3, pp 567–587

A Noninvasive Method for Estimating Nitrogen Balance in Free-Ranging Primates

  • Erin R. Vogel
  • Brooke E. Crowley
  • Cheryl D. Knott
  • Melissa D. Blakely
  • Michael D. Larsen
  • Nathaniel J. Dominy

DOI: 10.1007/s10764-011-9543-6

Cite this article as:
Vogel, E.R., Crowley, B.E., Knott, C.D. et al. Int J Primatol (2012) 33: 567. doi:10.1007/s10764-011-9543-6


The vital role of body protein as an energy reserve has received little focus in studies of wild primates. Owing to the relatively low protein content of fruit, some frugivorous primates could face a protein deficit if body protein is catabolized for energy during periods of low fruit availability. Such an imbalance can be detected if fatty acids, amino acids, and nitrogen (N) catabolites are reincorporated or recycled back to tissues. Here we describe a method to quantify protein recycling by measuring standardized urea concentration and N isotope signatures from urine samples collected from wild Bornean orangutans (Pongo pygmaeus wurmbii). Our overall goal was to explore if concentrations of urea and δ15N values could be used as indicators of the amount of protein consumed and the degree of protein recycling, respectively, in wild, free-ranging primates. We examine the relationships between urea concentration, δ15N values, protein intake, and fruit availability. Urea concentration increased with fruit availability, reflecting a slight increase in protein consumption when fruit was abundant. However, we found no relationship between δ15N values and fruit availability, suggesting that orangutans avert a negative protein balance during periods of low fruit availability. These noninvasive methods complement recent advances in primate energy balance research and will contribute to our understanding of adaptations of primates during periods of fruit shortage.


Creatinine δ15Orangutans Pongo pygmaeus wurmbii Protein Urea 

Supplementary material

10764_2011_9543_MOESM1_ESM.doc (113 kb)
ESM 1(DOC 113 kb)

Copyright information

© Springer Science+Business Media, LLC 2011

Authors and Affiliations

  • Erin R. Vogel
    • 1
    • 2
  • Brooke E. Crowley
    • 3
  • Cheryl D. Knott
    • 4
  • Melissa D. Blakely
    • 5
  • Michael D. Larsen
    • 6
  • Nathaniel J. Dominy
    • 7
  1. 1.Department of Anthropology and the Center for Human Evolutionary StudiesRutgers UniversityNew BrunswickUSA
  2. 2.The Center for the Advanced Study of Hominid Paleobiology, Department of AnthropologyThe George Washington UniversityWashingtonUSA
  3. 3.Departments of Geology and AnthropologyUniversity of CincinnatiCincinnatiUSA
  4. 4.Department of AnthropologyBoston UniversityBostonUSA
  5. 5.Department of Ocean SciencesUniversity of California Santa CruzSanta CruzUSA
  6. 6.Department of StatisticsThe George Washington UniversityWashingtonUSA
  7. 7.Department of AnthropologyDartmouth CollegeHanoverUSA

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