Development of ecological competence in Sumatran orangutans

Bibliographic Data

ID8319730
AuthorsMaria A Van Noordwijk (0000-0001-9633-0845, Duke University, corresponding author), C P Van Schaik (0000-0001-5738-4509, Duke University)
Year2005
Volume127
Issue1
Pages79-94
Publication date2005-05-01
Peer ReviewedYes
Open AccessYes
TypeARTICLE
VenueAmerican Journal of Physical Anthropology (JOURNAL)
Journal identifiersISSN: 0002-9483 • E-ISSN: 1096-8644
PublisherWiley (PUBLISHER • GB)
DOI10.1002/ajpa.10426
PMID15472890
OpenAlexW2091561394
LanguageEN
Citations received51
References cited43

Data on orangutans (Pongo pygmaeus abelii) living in a Sumatran swamp forest yield an estimated median interbirth interval of at least 8 years, concurring with findings from other sites. This longest known mammalian interbirth interval appears due to maternal amenorrhea during the long exclusive dependence of the offspring. We describe the development of various components of offspring independence. In this arboreal ape, 3-year-olds had largely reached locomotor independence. Nest-building skills were also well-developed in 3-year-olds, but immatures shared their mother's nest until weaned at around age 7. At time of birth of the new sibling, association with the mother had begun to decline for both male and female offspring, suggesting that the immatures had mastered all the necessary skills, including basic tool use, to feed themselves. By about 11 years of age, they also ranged independently from the mother. These results show that orangutans do not develop independence more slowly than chimpanzees. Why, then, is weaning 2 years later in orangutans? In chimpanzees, mothers are often accompanied by two or even three consecutive offspring, unlike in orangutans. This contrast suggests that an orangutan mother cannot give birth until the previous offspring is ecologically competent enough to begin to range independently of her, probably due to the high energy costs of association. Thus, the exceptionally long interbirth intervals of orangutans may be a consequence of their solitary lifestyle

Altricial · Arboreal locomotion · Biology · Cooperative breeding · Developmental psychology · Habitat · Nest (protein structural motif) · Offspring · Pongidae · Precocial · Pregnancy · Sibling · Troglodytes · Animal Vocal Communication and Behavior · Demography · Ecology · Human-Animal Interaction Studies · Primate Behavior and Ecology · Psychology