Researchers examine how pink sea urchins sharpen their teeth to develop self-sharpening tools
By Michael Alexander // Sep 23, 2020

Aside from their fearsome array of spines, sea urchins have another evolutionary edge over other sea creatures: self-sharpening teeth.


According to researchers from Northwestern University, the spiny invertebrates, unlike other animals whose teeth are built to resist constant wear and tear, have teeth engineered to chip and weather in such a way that they maintain their sharp edges.

The secret behind this lies in their teeth’s base materials.

"The material on the outer layer of the tooth exhibits a complex behavior of plasticity and damage that regulates 'controlled' chipping of the tooth to maintain its sharpness," explained Horacio Espinosa, director for Northwestern's theoretical and applied mechanics program and a co-author of the study.

For the study, which appeared in Matter, the team examined the teeth of pink sea urchins (Strongylocentrotus fragilis), which are abundant in the western coastlines of North America. They employed a combination of sophisticated mechanical testing and electron microscopy in order to capture 3D footage of sea urchin teeth and the wear that these experienced as they ground against a superhard material made of diamonds.

Their findings revealed that sea urchin teeth are actually composed of precisely-arranged ceramic composites. On the convex side of the tooth, calcite fibers provide structural integrity. This fibrous composite then transitions to another composite made of inclined calcite plates on the convex side of the tooth. These calcite plates, the researchers added, chip away at the tooth as it wears, allowing it to maintain optimal sharpness. (Related: Fascinating biology: Here’s why certain animals have DOZENS of bones in their skulls.)

“We found that the superior performance of the sea urchin dentition system emerges from tooth self-sharpening during the organism's life span,” Espinosa said. They also found that continuous tooth growth compensates for any tooth loss that happens within the animal's life span.

“We were awed by the fact that nature has found its way to tailor the design to optimize one animal in their habitat,” added co-author Hoang Nguyen.

In a statement, the team said their findings can help guide the design of similar self-sharpening cutting-edge tools.

Sea urchin teeth a template for new space exploration device

This is not the first time that the spiny sea creatures inspired the design of new technologies.

In 2016, a team of engineers and marine biologists at the University of California, San Diego designed a claw-like device inspired by the sea urchin's intricate mouth and teeth. This device, which they described in the Journal of Visualized Experiments, could be used to sample sediments on other planets, such as Mars.

According to Michael Frank from the Jacobs School of Engineering at UC San Diego and a co-author of the study, the sea urchin's extraordinary ability to rip through rock could translate to a good sediment sampler for space vehicles, such as the current crop of Mars rovers, which use automated shovels to collect samples.

“Our goal was a bioinspired device that's more precise and efficient at grabbing ground samples from different areas, and won't disturb the surrounding area like a shovel would," Frank said.

Sea urchins owe their stone-ripping capabilities to the presence of a structure in their teeth called keels. This T-shaped structure, the researchers said, helped lessen the stress experienced by teeth up to 16 percent. Their findings led to the development of a claw-like device that, according to the research team, can be attached to a fleet of mini rovers which could then be deployed to collect samples during Martian explorations.

Frank, in a statement, said he hopes that this design will become of interest to both the National Aeronautics and Space Administration (NASA) and Elon Musk’s SpaceX program.

Sources include:

Take Action:
Support NewsTarget by linking to this article from your website.
Permalink to this article:
Embed article link:
Reprinting this article:
Non-commercial use is permitted with credit to (including a clickable link).
Please contact us for more information.
Free Email Alerts
Get independent news alerts on natural cures, food lab tests, cannabis medicine, science, robotics, drones, privacy and more. © 2022 All Rights Reserved. All content posted on this site is commentary or opinion and is protected under Free Speech. is not responsible for content written by contributing authors. The information on this site is provided for educational and entertainment purposes only. It is not intended as a substitute for professional advice of any kind. assumes no responsibility for the use or misuse of this material. Your use of this website indicates your agreement to these terms and those published on this site. All trademarks, registered trademarks and servicemarks mentioned on this site are the property of their respective owners.

This site uses cookies
News Target uses cookies to improve your experience on our site. By using this site, you agree to our privacy policy.
Learn More
Get 100% real, uncensored news delivered straight to your inbox
You can unsubscribe at any time. Your email privacy is completely protected.