Last week, Janice Arnold and I took down our trial installation combining her felt and my feathers. Because of this collaboration, I am thinking about keratin, the protein that makes hair, skin, claws, beaks and feathers. It also makes spider webs and the baleen of whales.
You can start to get an idea of the shared function of this material just by asking what keratin does that is the same for all these things, from skin to claws. Keratin provides toughness.
It provides toughness because its protein building blocks are long and complex. Claws, beaks, hair, and feathers look different for two reasons. One, keratin comes in dozens of varieties. And two, like the same kinds of bricks go into building different structures, so can the same variety of keratin build different structures.