Prof. George Mayer and his team at the University of Washington have had some new success in imitating nature to create advanced materials. They have produced a brick-and-mortar style composite of ceramic and polymer which imitates the microstructure of mollusk shells, and it has proven to be six times tougher than a solid block of the ceramic.
The secret is to have squishy mortar instead of strong/brittle mortar. This allows the energy of cracks to be diverted into tortuous paths and multiple paths; it also causes increased crack surface area, pull-out of ceramic layers from the polymer, crack bridging by the polymer, and other effects. Two articles on the advance were published in last month's American Ceramic Society Bulletin, though a subscription is required in order to read it. (Though if someone's really dying to read the gory details, I have the articles.)