What Do Porcupine Quills and Toucan Beaks Have in Common?

Porcupine quills and toucan beaks have more in common that you’d imagine. They’re essentially hollow tubes of tough keratin, the same material our hair and nails are made of, stuffed with a foam-like material made of fibers and membranes.

You can learn more about the quills and beaks, as well as other interesting materials found in plants and animals in a review of the field of bio-inspired engineering and biomimicry published in the Feb. 15 issue of the journal Science and co-authored by Marc Meyers and Joanna McKittrick of the Jacobs School of Engineering at UC San Diego. 

Read the full story about the paper here . Then check out some great pictures of tough, strong and light biological materials on Flickr. Check out some examples below:

The African porcupine’s quills are made of keratin, the same material that makes hairs and nails, and consist of a dense outer shell surrounding a foam-like material.  By contrast, the American porcupine's quill is smaller and not as strong or stiff.

The interior of the toucan’s beak is rigid "foam" made of bony fibers and drum-like membranes sandwiched between outer layers of keratin, the protein that makes up fingernails, hair and horn.  The result is solid “foam” made of air-tight cells that gives the beak additional rigidity. 

An abalone shell is made of thousands of layers of “tiles” made of calcium carbonate (more commonly known as chalk). A key to the strength of the abalone shell is a protein adhesive that binds to the top and bottom surfaces of the calcium carbonate tiles. The glue is strong enough to hold layers of tiles firmly together, but weak enough to permit the layers to slip apart, absorbing the energy of a heavy blow in the process. The images on the right show the shell's structure under increased magnification. 

The longhorn cowfish, from the boxfish family, can be found in tropical and subtropical waters in the Pacific and Atlantic oceans. Its shell is a good example of a material that is both light and tough. It is made of mineralized scales that do not overlap and are held together by zipper-like connections. The scales rest on a bed of fibers that imparts flexibility to the fish’s carapace. These gold-on-black images were taken with micro-computed tomography. 

Sea horses get their exceptional flexibility from the structure of their bony plates, which form its armor. The plates slide past each other. Here the seahorse’s skeleton, as well as the bony
plates, are shown though a micro CT-scan of the animal.