Ask an Expert: The Superpowers of Shark Skin

Speed, deflection and protection… these may sound like superpowers, but they’re actually adaptations exhibited by animals in the natural world — and shark skin is a perfect example!

Shark skin is covered by a layer of dermal denticles, otherwise known as placoid scales, that are made of the same material as human and stingray teeth. These flat, triangular scales have a central cavity supplied with blood flow, and they’re covered with a layer of dentine (hard tissue) for added protection. Denticles also grow with the shark as it ages, forming fresh scales between existing ones to cover the newly exposed shark skin.

If you’ve ever run your hand along one of our chain dogfish in the Touch Tank, it probably felt smooth one way, but jagged and rough when you switched directions. This is due to the denticles’ formation, which gives shark skin a sandpaper-like texture. After repeated contact over an extended period of time, shark skin can actually create tiny slices on human skin. Our animal care team work closely with larger sharks and have described getting mild rashes due to the scales. Now we understand why “dermal denticles” literally translates to “skin teeth!”

While denticles vary in shape and size depending on the shark species, the scales have the same basic functions: hydrodynamics and protection. The placement of denticles on a shark’s body streamlines its movements in the water, reducing drag (resistance) and allowing the shark to swim quickly, efficiently and quietly. The denticles also add an imperceptible layer of defense, which is certainly handy when feeding alongside fellow sharks and other predators. It’s not uncommon for a shark to accidentally bite another when it’s dinner time, so having a little extra armor never hurts.

However, the protection that denticles offer sharks isn’t purely based on predatory or accidental attacks. These tiny scales offer protection from parasites, algae and barnacles as well. Due to the shape and structure of the tooth-like scales, these organisms find it difficult to attach to a shark’s body, therefore adding an extra layer of security from unwanted hitchhikers.

So, shark skin is pretty neat, right? It’s so neat that companies in multiple industries are mimicking these superpowers in their products! This process, called biomimicry, is when biological traits are copied to create and design synthetic materials. For example, Speedo® created a swimsuit material called “Fastskin,” which was modeled after the dermal denticles of a shark. The material did so well, in fact, that it was banned from competition following a string of record-breaking races — including in the Olympics!

Likewise, in the boating industry, shark skin traits have been mimicked in the use of anti-fouling paints for the bottoms of boats to lessen algae buildup and prevent animal attachment (like barnacles). In the medical field, a product inspired by dermal denticles is in the works that would prevent bacterial and contaminant growth on hospital surfaces.

Shark skin has even left an impact on the aerodynamic industry, including airplanes, drones and turbines. In a research study by Harvard University, it was found that 3D printed models of shortfin mako denticles reduced drag and significantly increased lift when placed on the surface of a wing. Using mimicked properties of shark skin could pave the way for new avenues of aerodynamic designs for flight. Who would have thought?

All this considered, it’s no surprise that sharks are at the top of the ocean food chain.

Want to witness a shark’s superpowers for yourself? Be sure to stop by our Touch Tank and experience dermal denticles by touching a chain dogfish, then head down to the Great Ocean Tank and see hydrodynamics in action as our sharks glide through the water!

A special thank you to our expert, Arnold Postell, dive safety officer and curator of large exhibits, for his time and knowledge in creating this blog.

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Published August 22, 2022