Cross-dressing in Chemical Cues: Exploring ‘She-maleness’ in Newly-emerged Male Garter Snakes

  • Michael P. LeMaster
  • Amber Stefani
  • Richard Shine
  • Robert T. Mason


She-males are male garter snakes that elicit courtship behavior from other males during the breeding season. Initially thought to consist of a small sub-set of males which retained their attractive nature throughout the breeding season, recent behavioral data suggests that most, if not all, males undergo a period of ‘she-maleness’ upon first emerging from winter hibernation before losing their attractive nature shortly after emergence. Utilizing behavioral experiments and chemical analyses, we sought to discern whether newly-emerged male red-sided garter snakes (Thamnophis sirtalis parietalis) display a pheromone profile similar to the female sexual attractiveness pheromone. Sequestered in the skin lipids of females and responsible for triggering male courtship behavior, this pheromone has been previously linked with long-term she-maleness in this species. Results from courtship trials demonstrated that newly-emerged males are attractive to other males, although not to the same degree as females. Subsequent chemical analyses of skin lipids from females and newly-emerged males showed no quantitative or qualitative difference in the components constituting the sexual attractiveness pheromone. Thus, it appears that the majority of males in this species emerge with a female-like pheromone profile and subsequent physiological changes, yet to be identified, are responsible for the short- vs. long-term nature of this phenomenon.


Breeding Season Methyl Ketone Small Female Courtship Trial Garter Snake 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Andrén, C. (1986) Courtship, mating and agonistic behavior in the free-living population of adders, Vipera berus (L.). Amphibia-Reptilia 7, 353–383.CrossRefGoogle Scholar
  2. Burghardt, G.M. (1980) Behavioral and stimulus correlates of vomeronasal functioning in reptiles: feeding, grouping, sex, and tongue use. In: D. Müller-Schwarze and R.M. Silverstein (Eds.), Chemical Signals—Vertebrates and Aquatic Invertebrates. Plenum Press, New York, pp. 275–301.Google Scholar
  3. Carpenter, C.C. and Ferguson, G.W. (1977) Variation and evolution of stereotyped behavior in repiles. In: C. Gans and D.W. Tinkly (Eds.), Biology of the Reptilia. Academic Press, New York, pp. 335–554.Google Scholar
  4. Ford, N.B. (1981) Seasonality of pheromone trailing behavior in two species of garter snake, Thamnophis (Colubridae). Southwest. Nat. 26, 385–388.CrossRefGoogle Scholar
  5. Gehlback, F.R., Watkins, J.F. and Kroll, J.C. (1971) Pheromone trail-following studies of typhlopid, leptotyphlopid, and colubrid snakes. Behaviour 40, 282–294.Google Scholar
  6. Halpern, M. (1987) The organization and function of the vomeronasal system. Annu. Rev. Neurosci. 10, 325–362.PubMedCrossRefGoogle Scholar
  7. LeMaster, M.P. and Mason, R.T. (2001) Evidence for a female sex pheromone mediating male trailing behavior in the red-sided garter snake, Thamnophis sirtalis parietalis. Chemoecology 11, 149–152.CrossRefGoogle Scholar
  8. LeMaster, M.P. and Mason, R.T. (2002) Variation in a female sexual attractiveness pheromone controls male mate choice in garter snakes. J. Chem. Ecol. 28, 1269–1285.PubMedCrossRefGoogle Scholar
  9. LeMaster, M.P. and Mason, R.T. (2003) Pheromonally mediated sexual isolation among denning populations of red-sided garter snakes, Thamnophis sirtalis parietalis. J. Chem. Ecol. 29, 1027–1043.Google Scholar
  10. Mason, R.T. (1993) Chemical ecology of the red-sided garter snake, Thamnophis sirtalis parietalis. Brain Behav. Evol. 41, 261–268.PubMedGoogle Scholar
  11. Mason, R.T. (1992) Reptilian Pheromones. In: C. Gans and D. Crews (Eds.), Biology of the Reptilia, Vol. 18. The University of Chicago Press, Chicago, pp. 115–216.Google Scholar
  12. Mason, R.T. and Crews, D. (1985) Female mimicry in garter snakes. Nature 316, 59–60.PubMedCrossRefGoogle Scholar
  13. Mason, R.T., Fales, H.M., Jones, T.H., Pannell, L.K., Chinn, J.W. and Crews, D. (1989) Sex pheromones in garter snakes. Science 245, 290–293.Google Scholar
  14. Mason, R.T., Jones, T.H., Fales, H.M., Pannell, L.K. and Crews, D. (1990) Characterization, synthesis, and behavioral response to sex pheromone in garter snakes. J. Chem. Ecol. 16, 27–36.CrossRefGoogle Scholar
  15. Moore, I.T., LeMaster, M.P. and Mason, R.T. (2000) Behavioural and hormonal responses to capture stress in the male red-sided garter snake, Thamnophis sirtalis parietalis. Anim. Behav. 59, 529–534.PubMedCrossRefGoogle Scholar
  16. Noble, G.K. (1937) The sense organs involved in the courtship of Storeria, Thamnophis, and other snakes. B. Am. Mus. Nat. Hist. 73, 673–725.Google Scholar
  17. Ross, P., Jr. and Crews, D. (1977) Influence of the seminal plug on mating behavior in the garter snake. Nature 267, 344–345.PubMedCrossRefGoogle Scholar
  18. Shine, R. and Mason, R.T. (2001) Courting male garter snakes use multiple cues to identify potential mates. Behav. Ecol. Sociobiol. 49, 465–473.CrossRefGoogle Scholar
  19. Shine, R., Harlow, P., LeMaster, M.P., Moore, I.T. and Mason, R.T. (2000a) The transvestite serpent: Why do male garter snakes court (some) other males? Anim. Behav. 59, 349–359.CrossRefGoogle Scholar
  20. Shine, R., Olsson, M.M. and Mason, R.T. (2000b) Chastity belts in garter snakes: the functional significance of mating plugs. Biol. J. Linn. Soc. 70, 377–390.CrossRefGoogle Scholar
  21. Shine, R., Phillips, B., Waye, H., LeMaster, M.P. and Mason R.T. (2001) Advantage of female mimicry to snakes. Nature 414, 267.PubMedCrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media,LLC 2008

Authors and Affiliations

  • Michael P. LeMaster
    • 1
  • Amber Stefani
  • Richard Shine
  • Robert T. Mason
  1. 1.Department of BiologyWestern Oregon University345 North Monmouth AvenueUSA

Personalised recommendations