Chameleons change colour to seduce potential mates, not to escape predators

Washington, January 29 : Chameleons have evolved the ability to change their colours due to the need to rapidly signal to other chameleons, and not the need to camouflage from predators, according to a new study.

University of Melbourne researchers Devi Stuart-Fox and Adnan Moussalli say that the dramatic colour changes of chameleons are tailored to aggressively display to specific competitors and to seduce potential mates.

Their findings suggest that the evolution of colour change serves to make chameleons more noticeable, which is inconsistent with the camouflage hypothesis.

The amount of colour change possible varies between species.

During the study, Stuart-Fox and Moussalli placed two male chamilions on a branch opposite each other, and measured the colour variation.

Upon comparison between species that can change colour dramatically and species that only change slightly, and considering their evolutionary interrelationships, the researchers came to the conclusion that dramatic colour change was consistently associated with the use of colour change as a social signal to other chameleons.

The researchers say that 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 colour changing abilities in order to camouflage.

The study has been published in the open-access journal PLoS Biology.

ANI