The masticatory apparatus of a sea urchin – commonly known as Aristotle’s lantern – includes five teeth, each held by a separate jaw in a circular arrangement.
Now, researchers from Northwestern University, US, say they have discovered how those teeth manage to keep themselves sharp.
Rather than simply resisting wear, they are built to chip in a way that helps them to maintain a keen edge – not unlike sharpening a knife by selectively removing material from the cutting edge.
“The material on the outer layer of the tooth exhibits a complex behaviour of plasticity and damage that regulates controlled chipping of the tooth to maintain its sharpness,” says Horacio Espinosa, lead author of a paper in the journal Matter.
To make up for the loss of material, he explains, an urchin’s teeth continue to grow throughout life.
While the findings are intriguing, Espinosa’s primary interest is in understanding the behaviour of natural and synthetic nanomaterials across different scales.
He says the new findings should help to guide the design of microstructure and the selection of material constituents for the design of tools for a range of cutting, grinding, and boring applications.
Read science facts, not fiction...
There’s never been a more important time to explain the facts, cherish evidence-based knowledge and to showcase the latest scientific, technological and engineering breakthroughs. Cosmos is published by The Royal Institution of Australia, a charity dedicated to connecting people with the world of science. Financial contributions, however big or small, help us provide access to trusted science information at a time when the world needs it most. Please support us by making a donation or purchasing a subscription today.