MELBOURNE, AUSTRALIA: Young male lizards in South Africa imitate females to fool aggressive older males into leaving them alone, in an example of transvestism in the natural world, researchers have found.

The lizards not only avoid fights but gain access to females under the nose of their more macho rivals, the South African and Australian researchers discovered.

They found that young male Augrabies flat lizards delayed displaying the extravagant coloration of sexually-mature males until they were able to defend themselves adequately.

"Experienced males will chase and bite their young rivals," said associate professor Martin Whiting of Johannesburg's University of the Witwatersrand.

"By delaying the onset of colour to a more convenient period, these males, termed she-males, are making the best of a bad situation."

Australian National University associate professor Scott Keogh said opting to become transvestites for a period offered young males a dual advantage.

"They can avoid potentially dangerous bouts with dominant males and still have access to normally inaccessible females," he said.

But, as with large hands and an Adam's apple in the human world, there is a flaw in the lizards' transvestite transformation.

Dominant males can detect transvestite's male hormones with their sensitive tongues, even if they are taken in by their female appearance.

University of Sydney researcher Jonathan Webb said this meant the she-males needed to be nimble to avoid advances from dominant males smitten by their fake female allure.

"Males are fooled by looks, but not by scent," he said.

"She-males are able to maintain this deception by staying one step ahead of a prying male, and thereby avoiding a nosey tongue that might give the game away."

The research was published in the journal Proceedings of the Royal Society. (AFP)