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Decaying wood is a sodium source for mountain gorillas
Jessica M Rothman1, Peter J Van Soest, Alice N Pell
1Department of Animal Science, Cornell University, Ithaca, NY 14853, USA. jmr12@cornell.edu
Biology Letters
|December 7, 2006
Summary
Mountain gorillas in Uganda eat decaying wood for essential sodium. This surprising behavior addresses a dietary deficiency common in tropical herbivores due to soil leaching.
Area of Science:
- Primate Ecology
- Animal Nutrition
- Behavioral Biology
Background:
- Mountain gorillas (Gorilla beringei beringei) exhibit puzzling wood-eating behavior in Uganda's Bwindi Impenetrable National Park.
- The consumed wood has low nutritional value (protein, sugar) and high lignin content, making its purpose unclear.
Purpose of the Study:
- To investigate the nutritional significance of decaying wood consumption in mountain gorillas.
- To determine the specific nutrient contributing to this behavior, addressing the puzzle of wood consumption.
Main Methods:
- Collected wood samples (eaten and avoided) and other gorilla food items.
- Analyzed the sodium content of all collected samples.
Main Results:
- Decaying wood was found to be substantially higher in sodium than other dietary items.
- Eaten wood pieces contained significantly more sodium than avoided pieces.
- Wood constituted only 3.9% of food intake but provided over 95% of dietary sodium.
Conclusions:
- Decaying wood is a critical sodium source for Bwindi mountain gorillas.
- This behavior compensates for sodium deficiency in tropical herbivores due to soil leaching and low plant sodium content.
- Decaying wood represents an unexpected but vital source of sodium for these primates.
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