Materials like sapphire, diamond, Kevlar and even spider silk are all well-known for their incredible strength.
Now there’s a new entrant into the conversation, and forgive them for being a bit late—they are snails, after all.
A recent scientific study published in the Journal of the Royal Society Interface has declared limpet teeth as the new official strongest natural material on earth. For those not up to date on gastropods, limpets are small sea snails that live in both fresh and salt water and use their super strong teeth to scrape food off rocks.
We’re talking tensile strength here, not hardness. Hardness and tensile strength are fairly different. A simplification would be that hardness is a resistance to scratching while tensile strength reflects a resistance to breaking.
What is it about limpet teeth that make them so strong?
The tiny teeth are made of very thin, tightly-packed fibers that contain the hard mineral goethite. At 1/100th the diameter of a human hair, the ultra-thin fibers create an almost flawless weave that trumps even man-made carbon fibers.
As the author of the study Professor Asa Barber of The University of Portsmouth put it:
“Generally a big structure has lots of flaws and can break more easily than a smaller structure, which has fewer flaws and is stronger. The problem is that most structures have to be fairly big so they’re weaker than we would like. Limpet teeth break this rule as their strength is the same no matter what the size.”
To gauge the fibers’ tensile strength, Professor Barber attached each end of a small piece of the material to a lever and pulled on the sample until it broke. He found that the material had a strength of 5 gigapascals, which is five times the strength of spider silk and even beats out Kevlar. The tensile strength in this case comes primarily from the structure at a macroscopic level, not the same as crystal structure, which is molecular.
In the future, Professor Barber hopes to see the fibrous structures of limpet teeth studied and used by engineers for high-performance applications, such as Formula One race cars and boat hulls.
Until then, the team at Rubicon gives limpets a tip of the hat for having teeth made of the strongest natural material on Earth.