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Low testosterone correlates with delayed development in male orangutans.
Melissa Emery Thompson1, Amy Zhou, Cheryl D Knott
1Department of Anthropology, University of New Mexico, Albuquerque, New Mexico, United States of America. memery@unm.edu
Plos One
|October 19, 2012
Summary
Male orangutans exhibit distinct developmental paths. Early-developing males show higher testosterone levels long after maturation, suggesting a life-history trait, not just a current state.
Area of Science:
- Primate reproductive biology
- Endocrinology
- Behavioral ecology
Background:
- Male orangutans (Pongo spp.) exhibit unique developmental plasticity, with some maturing rapidly while others remain in an arrested, adolescent-like state for years.
- The hormonal underpinnings and long-term implications of these divergent male life history strategies remain poorly understood.
- While higher androgens are linked to developed males, the role of steroid hormones in developmental timing variation has not been thoroughly investigated.
Purpose of the Study:
- To investigate variations in testosterone and cortisol production in relation to developmental timing in adult male orangutans.
- To determine if hormonal differences between precocious and arrested males persist beyond the developmental transition.
- To explore the potential of hormonal profiles as indicators of male life history strategies.
Main Methods:
- Collected blood samples from 18 fully-developed (flanged) male orangutans housed in U.S. captive facilities.
- Measured circulating levels of testosterone and cortisol.
- Analyzed hormonal variations in relation to developmental status (precocious vs. arrested), age, housing, and species.
Main Results:
- Testosterone levels did not significantly correlate with current age, housing, or species origin.
- Males that underwent precocious development exhibited significantly higher testosterone levels compared to those that experienced developmental arrest.
- Cortisol levels were not detailed in the provided abstract.
Conclusions:
- Hormonal differences, specifically higher testosterone in early-developing males, appear to be a stable trait associated with life history strategy rather than a transient state.
- These physiological differences are detectable long after the developmental transition, suggesting distinct endocrine profiles linked to male orangutan development.
- Further research is needed to understand the ontogeny of these testosterone differences and their impact on male behavior.
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