Chameleons change colours to bowl over opposite sex

London, Jan 29 (UNI) Chameleons change colours to impress the opposite sex and their rivals, not to blend with their surroundings as a camouflage.

According to a new study published in the journal PLoS Biology, the need to rapidly signal to other chameleons by being flashy has driven the evolution of this colour change trait, which contradicts the camouflage hypothesis.

The research, conducted by Dr Devi Stuart-Fox at the University of Melbourne and Adnan Moussalli University of KwaZulu Natal, South Africa, shows that the dramatic colour changes of South African dwarf chameleons they studied are tailored to aggressively display to competitors and to seduce potential mates.

Because these signals are quick - chameleons can change colour in a matter of a nanosecond - the animal can afford to make it obvious, as the risk that a predator will notice is limited, the researchers say.

This finding means that the evolution of colour change serves to make chameleons more eye catching, the complete opposite of the camouflage hypothesis, the Daily Telegraph reported.

The team measured colour change by setting up chameleon ''duels'': sitting two males on a branch opposite each other and measuring the colour variation.

They showed that dramatic change in appearance is consistently associated with the use of colour change as a social signal to other chameleons. The degree of change is not predicted by the amount of colour variation in the chameleons' habitat, as would be expected if chameleons had evolved such remarkable abilities in order to blend in.

Chameleons are squamates that belong to one of the best-known lizard families. The name ''chameleon" means ''Earth lion.'' Different chameleon species are able to change different shades which can include pink, blue, red, orange, green, black, brown and yellow.

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