A limpet is an aquatic snail with a shell broadly conical in shape. “Limpet” informally refers to any gastropod whose shell has no obvious coiling as in familiar garden snails or in winkles. Although all limpets are members of Gastropoda, the group is highly polyphyletic, meaning that the various lines that we call limpets have descended independently from different ancestral gastropods. This general category of conical shell is technically known as “patelliform”, meaning dish-shaped. Some species of limpet live in fresh water, but the majority are saltwater inhabitants. All members of the large and ancient marine clade Patellogastropoda are limpets, and within that clade the family Patellidae in particular are often called the “true limpets”. However, other groups, not in the same family, are also called limpets of one type or another because of the similar shapes of their shells. Examples include the Fissurellidae, which are known as the keyhole limpet family, contained in the clade Vetigastropoda, though many of the members of the Vetigastropoda do not have the morphology of limpets at all. Research performed at Queen Mary University of London and published in the Royal Society journal Interface in 2015 concluded that “the tensile strength of limpet teeth can reach values significantly higher than spider silk, considered to be currently the strongest biological material, and only comparable to the strongest commercial carbon fibres”. The tensile strength of the limpet teeth, which were able to withstand 4.9 GPa, was attributed to a high mineral volume fraction of reinforcing goethite nanofibres.