by Roberto — ...in the case of red par­rot feath­ers the pig­ment has the ad­ded be­ne­fit of pro­tect­ing the plu­mage from bac­te­ri­al de­gra­da­tion. To­day I stay on the to­pic of ani­mal co­lor­a­tion by de­scrib­ing the pe­culi­ar pe­lage pig­ment of sloths. Exact­ly what con­sti­tutes an eye-catch­ing color is, of course, in the eye of the be­holder.