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Asian Elephants: With Maturity, Chemical Balance

December 22, 2005

Male Asian elephants (Elephas maximus) are famed for their annual bouts of heightened sexual activity and aggression, called ‘musth,’ during which they produce a notoriously pungent cocktail of chemicals to advertise their mating status. New research shows that this recipe is delicately concocted—more mature males impress females by including a balance of different versions of a particular pheromone.

This pheromone, called frontalin, exists in two molecular ‘mirror-image’ forms, explain Elizabeth Rasmussen and her colleagues in a Brief Communication in the December 22, 2005 Nature. Young males tend to produce secretions that predominantly contain just one of these two chemical forms. But more mature males advertise their dominant status by achieving an equal balance of the two.

Secretions containing a 1:1 mixture of the two forms were more attractive to females, the researchers report, indicating that this subtle balance of chemicals might help females to distinguish between males of differing status. Female receptor molecules for these pheromones also come in two mirror-image forms, suggesting that cleverly mixed mating cocktails could reach the parts that others do not.

Abstract © 2005 Nature

“Chirality in elephant pheromones,” David R. Greenwood, Dan Comeskey, Martin B. Hunt, L. Elizabeth L. Rasmussen, Nature, December 22, 2005

Elizabeth Rasmussen, Oregon Health & Sciences University, Beaverton, OR