ARISTOTLE thought fear made chameleons change colour, while most of us assume it’s all about camouflage. But in dwarf chameleons, at least, it’s about sex and fighting too.
There are 14 species of dwarf chameleon across South Africa alone, and a further seven genetic subgroups, all of which boast differing colour-changing abilities. Living in habitats ranging from grassland to rainforest, they use colour changes along their flanks not only to hide, but for signalling. Males change colour to signal their interest in females and aggression to other males, even squaring up in rapid-fire signalling duels. So is colour-change more important for sex or for camouflage?
Devi Stuart-Fox and Adnan Moussalli at the University of Melbourne, Australia, collected males from all 21 genetic groups and watched them duel. They recorded their habitat-background colours and also the lizards’ changing hues.
Chameleons collected from brighter, more varied habitats did not reveal a greater