The 82nd Annual Meeting of the American Association of Physical Anthropologists (2013)


Nutritional ecology and nutrient balancing in a rainforest sifaka

MITCHELL T. IRWIN1, JESSICA M. ROTHMAN2, DAVID RAUBENHEIMER3, JEAN-LUC RAHARISON4 and COLIN A. CHAPMAN5,6.

1Department of Anthropology, Northern Illinois University, 2Department of Anthropology, Hunter College, 3Institute of Natural Sciences, Massey University, 4Department of Animal Biology, University of Antananarivo, 5Department of Anthropology, McGill University, 6McGill School of Environment, McGill University

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Despite advances in documenting macronutrient composition of wild primate foods, much less is known about constraints and goals governing absolute daily intakes and macronutrient balancing in the diet. There is increasing recognition that nutritional currencies are complex, some herbivores strictly regulate one or more macronutrients, and that the balance of dietary macronutrients has health consequences. In primates, Felton et al. (2009) found that spider monkeys prioritized protein intake while non-protein energy intake varied (“protein-leverage”); Rothman et al. (2011) found that mountain gorillas optimized non-protein energy intake, while protein intake varied. We describe a third pattern in diademed sifakas (Propithecus diadema). From July 2006-July 2007 we collected 140 sifaka food samples at Tsinjoarivo, Madagascar, which we analyzed for protein, fat, and carbohydrates, collected feeding data (363 days, 18,253 feeding bouts), and calculated daily macronutrient and energy intakes. Dry matter and all macronutrient intakes varied considerably across seasons (~four times higher in the rainy season), as animals switched to different foods. Although consumed foods varied widely in protein content (% of macronutrient energy derived from protein=15.02, SD=12.62, n=78), sifakas had unexpectedly consistent proportional protein intake: 9.35% (SD 2.49) of daily macronutrient energy supplied by protein. Nonprotein energy was dominated by carbohydrates, especially in the lean season. These data suggest that sifakas follow a nutrient-balancing strategy with respect to protein, optimizing proportions rather than amounts. Much remains to be learned about diversity in how primates prioritize macronutrients, and the effects of different strategies on food selection, activity levels, physiologic health, and feeding competition.

Supported by: Margot Marsh Biodiversity Foundation, NSERC.

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