David Schultz in ScienceShhot: Spider silk dethroned as nature’s toughest fiber:
Spider silk is famous for its amazing toughness, and until recently a tensile strength of 1.3 gigapascals (GPa) was enough to earn it the title of strongest natural material. However, researchers report online today in the Journal of the Royal Society Interface that the record books need to be updated to properly recognize the incredible strength of the limpet teeth. … [T]he limpets’ teeth boast a tensile strength of between 3 and 6.5 GPa, researchers report.