Limpets often suffer a lot of damage at the top of their conical shells. Rather than drying out or getting picked off by hungry seagulls, the creatures quickly patch over small holes with new biological building material from within, the research has found. These shellsare just as strong as the originals when subjected to impacts from rocks.
However, while the shells do resist single impacts from materials such as rocks and stones, the shells are less resistant to multiple impacts. Electron microscopy has shown that the layered structure of the shell makes it susceptible to “spalling”, a well-known cause of failure in engineering materials such as concrete that involves the material splitting into smaller pieces.
Speaking of his findings, Professor Taylor said: “you will see rocks covered with limpets along many seashores across the world. They have several features that make them interesting from a biomechanical point of view – they have evolved mechanisms for adhering very strongly to the underlying rock and are also equipped with a set of very hard teeth.”
“But they also have this very hard, stiff shell and it is this feature I was interested in knowing more about. It is incredible that they can repair their shells to be just as strong as the original ones, but it is also really interesting that they are still at risk from spalling weaknesses.” Taylor continued: “As engineers we often gain inspiration for solutions to real-world problems from nature, and from the way different plants and animals have adapted to life in harsh environments. Spalling is evidently one problem that doesn’t have a perfect solution – whether you are a concrete foreman overseeing a building site or a limpet trying to speedily repair his or her home on the seashore.”