Controlling light through photonic nanostructures are important for everyday optical components, from spectrometers to data storage. In nature, nanostructured materials produce wavelength-dependent colours that are key for visual communication across animals and act as signals for mates or predators alike. The striking appearance of many animals is not obtained by pigments but rather by nanostructuring dielectric material on the order of a few hundreds of nanometres. By changing the morphology of these nanostructures and the chemical composition, incident light can be manipulated in different ways giving rise to the brilliant displays observed in butterflies, beetles, spiders and birds. Pigmentation can often not be ignored and plays important roles in tuning and altering optical properties. Here, I will show the optical properties of different morphologies found across select biological species and show which tricks nature employs to achieve all colours of the rainbow with added functionality that may exceed a pure biological function, but serve as inspiration for bio-inspired materials.