With a name like ‘mussel’ one would expect that these bivalves must have one strong muscle to help them attach to rocks in order to prevent the risk of being torn by crashing waves and currents. But what helps these mussels stay attached to their home base is actually a collection of fine filaments known as byssus threads. And the secret to the strength of these byssus threads has now been unraveled by MIT research scientist Zhao Qin and professor of civil and environmental engineering Markus Buehler. Researchers found that the byssus threads are composed of a well-designed combination of soft, stretchy material on one end and much stiffer material on the other. Both materials, despite their different mechanical properties, are made of a protein closely related to collagen, a main constituent of skin, bone, cartilage and tendons.