Jump to ContentJump to Main Navigation
OrangutansGeographic Variation in Behavioral Ecology and Conservation$
Users without a subscription are not able to see the full content.

Serge A. Wich, S Suci Utami Atmoko, Tatang Mitra Setia, and Carel P. van Schaik

Print publication date: 2008

Print ISBN-13: 9780199213276

Published to Oxford Scholarship Online: May 2009

DOI: 10.1093/acprof:oso/9780199213276.001.0001

Show Summary Details
Page of

PRINTED FROM OXFORD SCHOLARSHIP ONLINE (www.oxfordscholarship.com). (c) Copyright Oxford University Press, 2019. All Rights Reserved. An individual user may print out a PDF of a single chapter of a monograph in OSO for personal use. date: 19 November 2019

Geographic variation in orangutan behavior and biology

Geographic variation in orangutan behavior and biology

Its functional interpretation and its mechanistic basis

Chapter:
(p.351) CHAPTER 24 Geographic variation in orangutan behavior and biology
Source:
Orangutans
Author(s):

Carel P. van Schaik

Andrew J. Marshall

Serge A. Wich

Publisher:
Oxford University Press
DOI:10.1093/acprof:oso/9780199213276.003.0024

Extensive field data are available for three (out of four) Pongo taxa: the Sumatran P. abelii and the Bornean P. pygmaeus wurmbii of west and central Kalimantan and P. p. morio of east Kalimantan and Sabah. The data show a strong west–east gradient in morphology, behavioral ecology, and life history. From west to east, relative jaw robusticity and tooth enamel thickness increase, the frequency of reliance on non-fruit fallback foods—in particular inner bark of trees—increases dramatically, female day journey length and home range size decreases, the frequency of fat mobilization (and probably deposition) increases (although this has not yet been measured in P. p. morio), brain size decreases, sensitivity to selective logging decreases, average density decreases, and interbirth interval decreases. Social organization shows a similar west–east gradient, with Sumatran orangutans exhibiting a greater degree of sociality by a number of measures, although variation within Borneo is less clear. On Borneo, there may be less developmental arrest, male long calls are slower and have fewer pulses per call, consortships tend to be shorter, and a higher proportion of matings are forced. Geographic variation in orangutan features is probably produced through a combination of plastic developmental responses, genetic differences and cultural processes. The chapter offers a new hypothesis for the adaptive significance of these differences, based on the observed reduction in mean level of fruit production and increased incidence of periods of extreme scarcity from west to east. We highlight important remaining questions.

Keywords:   reaction norms, subspecies, culture, field data, morphology, behavioral ecology, life history, brain size, logging, density, interbirth interval, social organization, sociability, developmental arrest

Oxford Scholarship Online requires a subscription or purchase to access the full text of books within the service. Public users can however freely search the site and view the abstracts and keywords for each book and chapter.

Please, subscribe or login to access full text content.

If you think you should have access to this title, please contact your librarian.

To troubleshoot, please check our FAQs , and if you can't find the answer there, please contact us .