Sexual selection, genital morphology, and copulatory behavior in male Galagos

  • A. F. Dixson
Special Issue: Galago Symposium, Part II


Variations in penile morphology among galago species are pronounced and complex. Comparative studies of galagos and other primate species show that elongation of the baculum (os penis)is associated with copulatory patterns involving a prolonged period of intromission. The enlarged penile “spines” of male galagos may be important in maintaining a genital “lock” during copulation. In primate species where females mate with a number of partners, sexual selection may have favored the rapid evolution of such features of penile morphology and masculine copulatory behavior. It is suggested that evolution of complex penile morphologies in galagos has been influenced by sexual selection and that such morphological variations are extremely useful in taxonomic studies.

Key words

galago primate evolution penile morphology sexual behavior 


  1. Barrett, E. B. M. (1985).The Ecology of Some Nocturnal Arboreal Mammals in the Rainforest of Peninsula Malaysia, Ph.D. thesis, University of Cambridge, Cambridge.Google Scholar
  2. Bearder, S. K. (1986). Lorises, bushbabies and tarsiers: Diverse societies in solitary foragers. In Smuts, B. B., Cheney, D. L., Seyfarth, R. M., Wrangham, R. W., and Struhsaker, T. T. (eds.),Primate Societies, Chicago University Press, Chicago.Google Scholar
  3. Charles-Dominique, P. (1977).Ecology and Behaviour of Nocturnal Primates, Duckworth, London.Google Scholar
  4. Charles-Dominique, P., and Bearder, S. K. (1979). Field studies of lorisid behavior: Methodological aspects. In Doyle, G. A., and Martin, R. D. (eds.),The Study of Prosimian Behavior, Academic Press, New York.Google Scholar
  5. Clark, A. B. (1985). Sociality in a nocturnal “solitary” prosimian:Galago crassicaudatus.Int. J. Primatol 6: 581–600.CrossRefGoogle Scholar
  6. Darwin, C. (1871).The Descent of Man and Selection in Relation to Sex, John Murray, London.Google Scholar
  7. Dixson, A. F. (1976). Effects of testosterone on the sternal cutaneous glands and genitalia of the male greater galago(Galago crassicaudatus crassicaudatus).Folia primatol 26: 207–212.PubMedCrossRefGoogle Scholar
  8. Dixson, A. F. (1983). The hormonal control of sexual behaviour in primates. In Finn, C. A. (ed.),Oxford Rev. Reprod. Biol. 5, Oxford University Press, Oxford, pp. 131–219.Google Scholar
  9. Dixson, A. F. (1989a). Baculum length and copulatory behavior in primates.Am. J. Primatol. (in press).Google Scholar
  10. Dixson, A. F. (1989b). Observations in the evolution of the genitalia and copulatory behavior in male primates.J. Zool. Lond. (in press).Google Scholar
  11. Dixson, A. F., and Van Horn, N.R. (1977). Comparative studies of morphology and reproduction in two subspecies of the greater bushbaby,Galago crassicaudatus crassicaudatus andG. c. argentatus.J. Zool. Lond. 183: 517–526.CrossRefGoogle Scholar
  12. Doyle, G. A., Pelletier, A., and Bekker, T. (1967). Courtship, parturition and mating in the lesser bushbaby(Galago senegalensis moholi) under seminatural conditions.Folia primatol. 7: 169–197.PubMedCrossRefGoogle Scholar
  13. Eaton, G. G., Slob, A. K., and Resko, J. (1973). Cycles of mating behaviour, oestrogen and progesterone in the thicktailed bushbaby(Galago crassicaudatus crassicaudatus) under laboratory conditions.Anim. Behav. 21: 309–315.PubMedCrossRefGoogle Scholar
  14. Eberhard, W. G. (1985).Sexual Selection and Animal Genitalia, Harvard University Press, Cambridge, Mass.Google Scholar
  15. Hill, W. C. O. (1953).Primates: Comparative Anatomy and Taxonomy, Vol. 1, Edinburgh University Press, Edinburgh.Google Scholar
  16. Hill, W. C. O. (1958). External Genitalia. In Hofer, H., Schultz, A., and Starck, D. (eds.),Primatologica, Vol. 3, Karger, Basel, pp. 630–704.Google Scholar
  17. Martin, R. D. (1981). Field studies of primate behaviour.Symp. zool. Soc. Lond. 46: 287–336.Google Scholar
  18. Nash, L. T., Bearder, S. K., and Olson, T. R. (1989). Synopsis ofGalago species characteristics.Int. J. Primatol. 10: 57–80.Google Scholar
  19. Olson, T. (1979).Studies on Aspects of Morphology of the Genus OtolemurCoquerel, 1859, Ph.D. thesis, University of London, London.Google Scholar
  20. Rudder, B. C. C. (1979).The Allometry of Primate Reproductive Parameters, Ph.D. thesis, University of London, London.Google Scholar
  21. Schultz, A. H. (1969).The Life of Primates, Weidenfeld and Nicolson, London.Google Scholar
  22. Sokal, R. R., and Rohlf, F. J. (1969).Biometry, Freeman, San Francisco.Google Scholar

Copyright information

© Plenum Publishing Corporation 1989

Authors and Affiliations

  • A. F. Dixson
    • 1
  1. 1.MRC Reproductive Biology UnitCentre for Reproductive BiologyEdinburghUK

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