Early sexual maturity in male hamadryas baboons (Papio hamadryas hamadryas) and its reproductive implications
Article first published online: 5 DEC 2005
Copyright © 2005 Wiley-Liss, Inc.
American Journal of Physical Anthropology
Volume 129, Issue 4, pages 584–590, April 2006
How to Cite
Zinner, D., Krebs, E., Schrod, A. and Kaumanns, W. (2006), Early sexual maturity in male hamadryas baboons (Papio hamadryas hamadryas) and its reproductive implications. Am. J. Phys. Anthropol., 129: 584–590. doi: 10.1002/ajpa.20344
- Issue published online: 13 MAR 2006
- Article first published online: 5 DEC 2005
- Manuscript Accepted: 6 MAY 2005
- Manuscript Received: 17 SEP 2004
- hamadryas baboon;
- life history;
- sexual maturity;
- mating system
We present data on sexual maturity in young hamadryas baboon males (Papio hamadryas hamadryas) and its reproductive consequences in a large captive baboon colony. Hamadryas baboons live in a multilevel social system, with one-male units (OMUs) as the smallest social entity. Male leaders of OMUs are believed to monopolize matings within their OMUs; hence mating is believed to be polygynous and monandrous. In a captive colony of hamadryas baboons, we found evidence that young males less than 4 years old fathered at least 2.5% of 121 offspring born subsequent to vasectomy of all adult males, and males aged 4–5 years fathered at least 16.5% of the offspring. Additional evidence that these young males are able to sire offspring came from a morphological comparison of sperm from hamadryas males of different ages. The sperm of a 48-month-old hamadryas baboon were morphologically indistinguishable from viable sperm from adult males, whereas sperm from a 45-month-old male showed some aberrations. If successful copulations by adolescent males constitute a regular pattern even in free-ranging hamadryas baboons, a hamadryas male's chances to reproduce would not be limited to his role as an OMU leader as previously assumed, and a male's reproductive career would consist of two phases: the adolescent phase, and the OMU leader male phase. Am J Phys Anthropol, 2006. © 2005 Wiley-Liss, Inc.