Scientists in the US have solved one of nature's little mysteries – how the harlequin mantis shrimp can generate enough force to smash aquarium glass, without doing any significant damage to its pair of "dactyl" clubs. The researchers believe that the secret of the clubs, which are normally used by the shrimp to crack open tough shellfish, lies in how they combine materials with very different properties. Measurements reveal that the clubs have a much higher specific strength and toughness than any synthetic composite material – a finding that the researchers think could lead to stronger materials, including those for use in body armour