Ad

Why is shark skin so rough?

The dermal denticles of a shark seen under an electron microscope.

By Blaise Jones

Shark skin is often described as feeling like sandpaper, but in actuality it’d be more appropriate to say that sandpaper feels like shark skin. After all, humans used shark skin as sandpaper before sandpaper was even invented! What benefits do sharks gain from having such tough skin?

Swimming by the Skin of your Teeth

Shark skin is coated in a series of scales called dermal denticles. Made of substances similar to teeth, these denticles are anchored into their skin via roots and have a pulpy center coated in a layer of dentine and enamel, two of the hardest biologically occurring substances.

Just like shark teeth, these denticles have points. To help reduce drag while swimming, the denticles point toward the tail. Rubbing one’s hand against the skin, rubbing from the tail toward the head against the flow of the dermal denticles, he can easily produce a rash and some shark skin is so sharp they can actually cut the skin.

But even if you rub a shark the right way, why is it so rough?

Energy Saving Enamel

Even if you don’t rub a shark the wrong way, their skin is still rough. Each and every dermal denticle on a shark’s skin has a series of ridges and grooves. These ridges and grooves are designed to reduce the drag produced by water moving along the shark’s skin as it swims. These grooves actually repel the water off the shark’s skin allowing them to move both speedily and stealthily through the water.

Shark skin is so efficient at repelling water that scientists have found it can reduce drag by 8.7 percent. When combined with a shark’s typical “S” shaped swimming pattern, drag is reduced by 15 percent. That translates to a 6.6 percent increase in swimming speed and a 5.9 percent reduction of energy consumption.

But why are scientists so fixated on shark skin?

ROBO-SHARK

The figures listed above came from a lab testing artificial shark skin. Using the latest in 3D printing technology, scientists have been able to combine the unique shape of shark scales with flexible materials, in essence creating artificial shark skin.

Previous research into shark skin has led to everything from professional swim suits to fighter jets doing their best to mimic the material, but this is one of the first cases of a one-to-one replica of shark skin being created. And while swimsuits do come to mind when practical applications of this material is brought into question, some scientists have mechanized machinations in mind.

Some scientists want to create “soft bodied” under water robots coated in this water repelling, energy saving material. These roboticists have already taken inspiration from nature, using octopus as the template for the first ever soft-bodied robot. Coating these soft-bodied octo-bots with artificial shark skin would greatly increase their movement speed underwater while also reducing their energy consumption.

A comparison of the dermal denticles of different sharks.

SOURCES:

“The Encyclopedia of Sharks” by Steve Parker

“Sharks: The Animal Answer Guide” by Gene Helfman and George H. Burgess

http://gizmodo.com/scientists-finally-understand-shark-skin-thanks-to-3d-1577091399

http://www.enchantedlearning.com/subjects/sharks/anatomy/Skin.shtml

http://www.sharksinfo.com/skin.html

http://www.primitiveways.com/processing_sharkskin.html

https://www.sharecare.com/health/teeth-basics/what-is-dentin?logref=Helpful_Button&regref=Helpful_Button

http://www.sciencemag.org/news/2016/08/octobot-world-s-first-soft-bodied-robot

http://www.imdb.com/title/tt1619880/

-TSF-

#sharks #sharkskin #denticles #dermaldenticles #TSF