Normally colour is derived from pigment. This makes it possible to colour clothes, foods, paint etc by simply adding various pigments to the underlying substance.
Iridescent colour does not result from pigment but from sub-micron structures that causes interference and diffraction of light. This is called structural colour.
It appears that the peacock’s, bright iridescent feathers may be covered in brown (melanin) pigment. The pigment appears to absorb background light and in doing so make the iridescent colour appear more vivid.
Why do the Afrikaans speaking people refer to a grey rhinoceros as white? The popular etymological story goes like this:
The Dutch at the Cape of Good Hope called the white rhinoceros the “wide” (Dutch: wijd, Afrikaans: wyd) rhinoceros to refer to its wide mouth adapted for grazing – a grass eater. Its mouth is an anatomical feature that distinguishes it from the black rhinoceros, which is a browser – a leaf eater.
The English misheard/mistranslated ‘wijd’ and started calling the rhino “white”.
Some years later, the Dutch/Afrikaners on hearing that the English refer to this rhino as white, decided to use the Afrikaans translation for white rather than stick with the anatomically correct name they purportedly gave it earlier.
You won’t be alone in your incredulity; Kees Rookmaaker, Chief Editor of the Rhino Resource Center wrote in a 2003 publication “the popular explanation that ‘white’ is derived from the Afrikaans word ‘wyd’ is examined and found to be unsubstantiated and historically incorrect.”
The purpose of the black and white stripes on zebra has been the subject of some speculation. One suggestion is that stripes make it difficult for predators to single out an individual zebra from the herd, but experimental evidence to support that and other ideas has been lacking.
Turns out bloodsucking horseflies and tsetse flies who do not only deliver nasty bites but also carry dangerous germs find zebra stripes less attractive than uniform colouration.