First off, snails have teeth. The average garden snail has over 14,000 of them, which are arranged in rows on their tongue. The typical snail tongue, called a radula, might have 120 rows of 100, although some species may have more than 20,000 teeth.
But let’s talk about the ones in water. The limpet, an aquatic snail that feeds by scraping algae off of rocks, has been found to have teeth that exceed the tensile strength of spider silk, Kevlar, and titanium.
Researchers measured that the amount of force required to break the millimeter long teeth is about the same pressure that it takes to turn carbon into diamond in the Earth’s crust ( about 5 gigapascals (GPa) – some five times greater than most spider silk. ) The authors of the study, which appears at the Journal of the Royal Society Interface, note:
“[Our] observations highlight an absolute material tensile strength that is the highest recorded for a biological material, outperforming the high strength of spider silk currently considered to be the strongest natural material, and approaching values comparable to those of the strongest man-made fibres.”