title: Nutritional ecology of wild Bornean orangutans (Pongo pygmaeus wurmbii) in a peat swamp habitat: Effects of age, sex, and season.
abstract: The spatial and temporal variation in food abundance has strong effects on wildlife feeding and nutrition. This variation is exemplified by the peatland forests of Central Kalimantan, which are characterized by unpredictable fruiting fluctuations, relatively low levels of fruit availability, and low fruit periods (<3% of trees fruiting) that can last nearly a year. Challenged by these environments, large, arboreal frugivores like orangutans must periodically rely on non-preferred, lower-quality foods to meet their nutritional needs. We examined variation in nutrient intake among age-sex classes and seasons over a 7-year period at the Tuanan Orangutan Research Station in Central Kalimantan. We conducted 2,316 full-day focal follows on 62 habituated orangutans (Pongo pygmaeus wurmbii). We found differences in total energy and macronutrient intake across age-sex classes, controlling for metabolic body mass. Intake of both total energy and macronutrients varied with fruit availability, and preference of dietary items increased with their nutritional quality. Foraging-related variables, such as day journey length, travel time, and feeding time, also varied among age-sex classes and with fruit availability. Our results add to the growing body of literature suggesting that great variation in foraging strategies exists among species, populations, and age-sex classes and in response to periods of resource scarcity.
  
  
  
  The spatial and temporal variation in food abundance has strong effects on wildlife feeding and nutrition. Here we present the first long term study of the effects of variation in fruit availability and age/sex class on nutritional ecology of wild Bornean orangutans. We examined variation in nutrient intake of wild orangutans in living in a peat swamp habitat over a 7-year period at the Tuanan Orangutan Research Station in Central Kalimantan. We conducted 2,316 full-day focal follows on 62 habituated orangutans (Pongo pygmaeus wurmbii). We found differences in total energy and macronutrient intake across age-sex classes, controlling for metabolic body mass. Intake of both total energy and macronutrients varied with fruit availability, and preference of dietary items increased with their nutritional quality. Foraging-related variables, such as day journey length, travel time, and feeding time, also varied among age-sex classes and with fruit availability. Our results add to the growing body of literature suggesting that great variation in foraging strategies exists among species, populations, and age-sex classes and in response to periods of resource scarcity.
authors.affiliation: Department of Anthropology, Rutgers University, New Brunswick, New Jersey.|The Center for Human Evolutionary Studies, Rutgers University, New Brunswick, New Jersey.|Graduate Program in Ecology and Evolution, Rutgers University, New Brunswick, New Jersey.
authors.forename: Erin R
authors.initials: ER
authors.lastname: Vogel
authors.affiliation: Department of Anthropology, Rutgers University, New Brunswick, New Jersey.|The Center for Human Evolutionary Studies, Rutgers University, New Brunswick, New Jersey.
authors.forename: Shauhin E
authors.initials: SE
authors.lastname: Alavi
authors.affiliation: Falkutas Biologi, Universitas Nasional Jakarta, Jakarta, Indonesia.
authors.forename: Sri Suci
authors.initials: SS
authors.lastname: Utami-Atmoko
authors.affiliation: Anthropological Institute and Museum, University of Zürich, Zürich, Switzerland.
authors.forename: Maria A
authors.initials: MA
authors.lastname: van Noordwijk
authors.affiliation: Department of Anthropology, Rutgers University, New Brunswick, New Jersey.|The Center for Human Evolutionary Studies, Rutgers University, New Brunswick, New Jersey.
authors.forename: Timothy D
authors.initials: TD
authors.lastname: Bransford
authors.affiliation: Department of Anthropology, Rutgers University, New Brunswick, New Jersey.|The Center for Human Evolutionary Studies, Rutgers University, New Brunswick, New Jersey.
authors.forename: Wendy M
authors.initials: WM
authors.lastname: Erb
authors.affiliation: Falkutas Biologi, Universitas Nasional Jakarta, Jakarta, Indonesia.
authors.forename: Astri
authors.initials: A
authors.lastname: Zulfa
authors.affiliation: Borneo Orangutan Survival Foundation, Bogor, Indonesia.
authors.forename: Fransiska
authors.initials: F
authors.lastname: Sulistyo
authors.affiliation: Research Center for Biology, Indonesian Institute of Sciences (LIPI), Cibinong-Bogor, Indonesia.
authors.forename: Wartika Rosa
authors.initials: WR
authors.lastname: Farida
authors.affiliation: Department of Anthropology, Hunter College of the City University of New York, New York, New York.
authors.forename: Jessica M
authors.initials: JM
authors.lastname: Rothman
mesh_terms: D000818:Animals; D017753:Ecosystem; D005247:Feeding Behavior; D057079:Pongo; D011148:Pongo pygmaeus; D012621:Seasons; D012987:Soil; D053833:Wetlands
chemical_list: D012987:Soil
keywords: Borneo; energetics; fallback foods; food preference; nutrition; orangutans; peatland