Velvety skin

08augustus2013
Source text and photo: sciencemag.org/sciencenow
In their rainforest habitat, West African Gaboon vipers lie for hours in wait until tasty prey comes along. Then they strike like lightning, immobilising their prey with their poisonous fangs.
The prey of the Gaboon viper (Bitis rhinoceros) consists of small mammals, birds living on the ground, and frogs and lizards. Markings on the snake’s skin provide the animal with good camouflaging. Its brown, black, and lighter spots make it nearly invisible in the shadows on the floor of the rainforest. The black spots are especially interesting, as they are a velvety black not often seen in animals. Scientists have now studied the molecular structure of these black spots. Under the scanning electron microscope, a pattern was seen of towers 30 microns high, with ridged edges (see inset photo). Optic tests showed that these structures reflect less than 11 per cent of light, as compared to the 27 per cent reflected by the other spots on the snakes. Regardless of the angle from which the black spots are viewed, they are always jet black.