Chameleons change colour 'to seduce potential mates'
Chameleons change colour to give out social signals
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Wednesday, 30, Jan 2008 01:19
Chameleons' ability to change colour has evolved due to the need to give out social signals rather than to camouflage, scientists claim.
A new study says the need to rapidly signal to other chameleons is more important for the creature than to hide from predators.
Researchers Devi Stuart-Fox and Adnan Moussalli found that the dramatic colour changes are tailored to aggressively display to competitors and to seduce potential mates.
Writing in the journal PLoS Biology, the researchers say because these colour signals are so quick - a matter of milliseconds - chameleons can afford to make it obvious as the risk that a predator will notice is limited.
Their findings are based on the study of chameleon 'duels' - sitting two males on a branch opposite each other and measuring the colour variation.
They found 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 colour changing abilities in order to camouflage.
"Capacity for colour change is unrelated to variation in the environmental backgrounds that chameleons must match in order to be camouflaged," the study says.
"Overall, our results suggest that the evolution of the ability to exhibit striking changes in colour evolved as a strategy to facilitate social signalling and not, as popularly believed, camouflage."