Let it shine!
Admire the most incredible iridescent animals
In most species, organic compounds called pigments create their colours and patterns, but there are a few that do things differently: the iridescent animals.
Iridescence is a phenomenon caused by the reflection and refraction of light waves, producing shimmering colours that seem to change depending on the angle the surface is viewed from.
Feathers, scales, fur and exoskeletons with complex structures can all generate this effect. When light hits them some waves are reflected straight off the outer surface, while others travel deeper until they’re reflected away by an inner layer. When these waves meet they can cancel each other out if their crests and troughs are out of sync (called destructive interference) or amplify each other to produce an unusually strong reflection if they match up (constructive interference).
Iridescence varies in its usefulness. Some animals rely on it in their quest to secure a mate, others have to avoid it getting them into trouble, and the rest don’t seem to notice it at all.