Biomimicry as a route to new materials: what kinds of lessons are useful?

We consider the attributes of a successful engineered material, acknowledging the contributions of composition and processing to properties and performance. We recognize the potential for relevant lessons to be learned from nature, at the same time conceding both the limitations of such lessons and our need to be selective. We then give some detailed attention to the molecular biomimicry of filamentous phage, the process biomimicry of silk and the structure biomimicry of hippopotamus 'sweat', in each case noting that the type of lesson now being learned is not the same as the potential lesson that originally motivated the study.