New search
download case
  • Overview
  • Teaching Notes
  • Answer Key
  • Comments/Replies

The Case of the Sexually Arrested Orangutans

Co Authors:

Susan B. Chaplin
Department of Biology
University of St. Thomas

Laura J. Baumgartner
Department of Biology
University of St. Thomas


This case examines the hormonal control of the development and maturation to adulthood and the role of stress hormones in that developmental process. The case was adapted from results summarized in Maggioncalda and Sapolsky’s (2002) article in Scientific American. It presents evidence for why an unusual adaptation for reproduction in subordinate male primates may have evolved as a means of reducing stress. Students are presented with data from the published studies and asked to analyze and interpret the results to formulate hypotheses. Initially developed for an upper division endocrinology course, the case has been used in an upper division comparative anatomy-physiology course, and could be used in an animal behavior or behavioral ecology course.

  • Understand the normal homeostatic regulation of peripheral endocrine glands, such as the adrenal and gonadal glands by the hypothalamus and pituitary.
  • Describe how one life process such as growth and maturation is regulated by a variety of synergizing hypothalamic and pituitary hormones.
  • Describe the action of stress hormones on normal physiology.
  • Understand the “fight or flight” response.
  • Appreciate the effect of stress hormones on growth and development.
  • Understand the effect of hormones on behavior.
  • Evaluate data to determine whether it supports hypotheses.
  • Generate new hypotheses based on results presented.
Keywords: Orangutan; ape; primate; secondary sexual development; endocrine hormones; stress hormones; cortisol; alternative reproductive strategies; evolution; arrested development
Topical Area: Scientific method
Educational Level: Undergraduate upper division
Formats: PDF
Type/Method: Interrupted, Journal Article
Language: English
Subject Headings: Physiology   Evolutionary Biology   Zoology  
Date Posted: 01/13/09
Date Modified: N/A
Copyright: Copyright held by the National Center for Case Study Teaching in Science, University at Buffalo, State University of New York. Please see our usage guidelines, which outline our policy concerning permissible reproduction of this work.

Teaching Notes

Case teaching notes are password-protected and access to them is limited to paid subscribed instructors. To become a paid subscriber, begin the process by registering here.

Teaching notes are intended to help teachers select and adopt a case. They typically include a summary of the case, teaching objectives, information about the intended audience, details about how the case may be taught, and a list of references and resources.

  Download Teaching Notes

Answer Key

Answer keys for the cases in our collection are password-protected and access to them is limited to paid subscribed instructors. To become a paid subscriber, begin the process by registering here.

  Get Answer Key

City State:
security code
Enter Security Code: