The thin threads that attach mussels to rocks and fast-moving ships have the perfect ratio of components to absorb the battering forces of the sea.

Civil engineers Markus Buehler and Zhao Qin of the Massachusetts Institute of Technology in Cambridge measured the strength of the mollusc's 'byssal threads', secreted protein fibres that extend from its shell to a hard surface. Using computer simulations, they found that the 4:1 ratio of soft to stiff material in natural threads minimizes the force experienced where threads join the shell, allowing the attachment to withstand crashing wave forces up to nine times the strength of the threads as measured with a stationary load.

The authors suggest that the insights could help researchers to design earthquake-resistant buildings, which, like mussels, must withstand fluctuating forces.

Nature Commun. 4, 2187 (2013)