Cross-dressing cuttlefish is Casanova of the reef

Scientists call it "facultative female mimicry" but to everyone else it is known as cross-dressing and the leading exponent of the art was revealed yesterday as the humble cuttlefish.

Scientists call it "facultative female mimicry" but to everyone else it is known as cross-dressing and the leading exponent of the art was revealed yesterday as the humble cuttlefish.

A pioneering study of the giant cuttlefish's sex life has revealed that some males pose as females to mate furtively beneath the noses of other males.

Marine biologists spent hundreds of hours diving off a remote Australian coral reef to film the sneaky antics of some male cuttlefish who donned female colouring and behaviour to get past males guarding a female. In less than a second, a male cuttlefish can pull in his telltale fourth arms - which are distinctively white - and change his skin colour to a mottled, female-like complexion.

Carrying his other arms in the typical posture of egg-laying females, the cross-dressed male sidles up to a receptive female and copulates with her while her butch-looking mate looks the other way.

The scientists, from Royal Holloway, University of London, the Marine Biological Laboratory in Massachusetts and Flinders university in southern Australia, said the cross-dressing tactic was surprisingly successful at fertilising eggs.

Using DNA fingerprinting, the scientists found the mimickers were successful in fertilising females 60 per cent of the time, which they say was surprising given that female cuttlefish typically reject 70 per cent of the sexual advances of ordinary males.

In a study in the journal Nature, they say: "We found female mimickers could successfully deceive the consort male and that they were able to position themselves near the female in 30 out of 62 attempts."

Roger Hanlon, of the Marine Biological Laboratory, said male cuttlefish could switch between a male and a female appearance as often as 10 times every 15 minutes and the disguise was so convincing other males even tried to copulate with cross-dressed brethren. "Sexual mimicry in animals is readily seen, but successful mating by mimics is rare," he said.