homehome Home chatchat Notifications


Pink sea urchins have self-sharpening teeth

The animals regularly sharpen the edge of their teeth like you would with a knife.

Tibi Puiu
September 19, 2019 @ 9:17 pm

share Share

The Internal jaw apparatus of an Aristotle’s lantern (the sea urchin’s chewing organ). Credit: Horacio Espinosa.

Sometimes called sea hedgehogs because of their tiny bodies covered in spines, sea urchins are remarkable creatures. On the opposite side of their thorny upper body, sea urchins have a mouth with five teeth, each held by a separate jaw. Astonishingly, these teeth sharpen themselves not too different from how you’d grind a kitchen knife, a new study found.

The urchins selectively chip away material from their teeth to maintain a sharp edge. Horacio Espinosa, along with colleagues at Northwestern University, discovered this amazing trait after they used electron microscopy to record 3-D movies showing how the pink urchin’s teeth wear.

According to the findings, the urchin’s teeth are made of ceramic composites arranged in an ordered and precise manner. Calcite fibers disposed on the convex side provide the teeth enhanced structural integrity while the convex side is made of incline calcite plates. As the tooth wears, the calcite plates chip away, sharpening the teeth.

The urchins don’t eventually lose their teeth because they constantly grow them throughout life.

Five sea urchin tooth tips stacked atop one another within the jaws. Credit: Horacio Espinosa

These findings provide new insights into the remarkable lives of sea urchins. But, Espinosa is more interested in the nanomaterial side of the story. He hopes that his work might one day lead to novel materials and microstructures for tools with a wide range of applications, such as cutting, grinding, and boring.

“I am exploring ways to do additive manufacturing of materials that can exhibit the performance of natural materials,” he says.

This wouldn’t be the first time that sea urchins inspire the design of new tools. Previously, aerospace engineers mimicked the sea creature’s star-shaped mouths in a claw-like scoop that can take sediment samples during missions on Mars or other worlds.

The findings were reported in the journal Matter.

share Share

Tiny Chinese Satellite Sent Hack-Proof Quantum Messages 12,900 Kilometers Through Space. Is a Quantum Internet Around the Corner?

The US and Europe are now racing to catch up to China.

Cats Came Bearing Gods: Religion and Trade Shaped the Rise of the Domestic Cat in Europe

Two groundbreaking studies challenge the old narrative that cats followed early farmers into Europe.

The People of Carthage Weren’t Who We Thought They Were

The Punic people had almost no genetic ties to Phoenicians, even though the latter founded the great city of Carthage.

RFK Jr loves raw milk. Now, he's suspending milk quality tests due to Trump cuts

Imagine pouring a glass of milk for your child and wondering if it’s safe.

A Roman gladiator died fighting a lion in England and his 1,800-year-old skeleton proves it

It's the first-ever evidence of man-lion combat found in the Roman period.

This Surprising Protein Shift Could Add Years to Your Life, Study Finds

A global study ties plant protein to longer adult lives, but early life needs differ.

Scientists Create a 'Power Bar' for Bees to Replace Pollen and Keep Colonies Alive Without Flowers

Researchers unveil a man-made “Power Bar” that could replace pollen for stressed honey bee colonies.

First-Ever Footage Captures a Living Colossal Squid—And It’s Just a Baby

A century after its discovery, the elusive giant finally reveals itself on camera.

Ancient tree rings reveal the hidden reason Rome’s grip on Britain failed

Three scorching summers in antiquity triggered revolt, invasion, and a turning point in British history.

Oxford Academics Used a Human Skull as a Wine Cup—Until 2015

It sounds like a scene from gothic fiction, but it’s real.