Nature's Velcro™

Certain Plant Adaptations Were the Inspiration for Velcro™

Since the development of the commercial product known as Velcro™, humans have used the invention as fasteners for shoes, garments, handbags, and a variety of other purposes. The product consists of two strips of material covered by hooks and loops. When the two strips are pressed together, the hooks grab loops and the sheer numbers of connections make the two strips hold together.

Velcro was patented in 1951 by George de Mestral, who had noticed burrs that stuck to his woolen hunting clothes while he grew up in Switzerland. He magnified the burrs and saw the hooks by which they held on, and then he engineered his invention. The name Velcro came from the French words for velvet (velour) and hook (crochet).

Hooks like the ones seen by de Mestral are used by local plants to disperse their seeds. Groups of seeds called “beggar lice” hitch a ride on the fur of mammals (or clothing of humans). The plant produces seeds in rows at the tips of stems (see photo at top of article). Mature seed coats are covered with hooks that help the seeds hold on to any animal that brushes by the plant. Later, and at another location, the animal removes the bothersome seeds by brushing or rubbing. As a result, the plant succeeds with its adaptation to disperse its seeds. These photos show seeds known as “beggar lice” sticking to denim jeans (above), and the hooks (left, greatly magnified) used to grab passing organisms.

Birds use the same principal to allow them to fly. Birds must be light enough to overcome gravity and let them stay in the air. Scale-like feathers could add weight and might bend or break, so some adaptation was needed to allow durable flexibility. Feathers serve the purpose because they are made of interlocking fiber-like strands. A feather is made of a long, hollow shaft called the quill. This tube is fringed on the sides by fibers called barbs, which themselves have smaller side branches called barbules. Hooklets curl from the barbules so they can hold on to adjacent barbules. The photos show different degrees of magnification so all of these structures can be seen.

When enough force causes the hooklets to lose their hold, and the feather appears to tear, there actually is no damage. When birds preen, they push the hooklets and barbules back together and restore the continuity of the feather – using the same principal as used in Velcro. These photos show a tail feather from a cardinal that looks torn. Magnified details (top) shows some barbs as dark lines, and barbules spreading from them at the “tear.” Greater magnification of barbules (bottom) reveals the hooklets that hold the feather together.

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