When I first started diving in Long Island Sound more than forty years ago, my first wetsuit was a sharkskin model named for all the little neoprene bulges that were supposed to better retain heat. I don’t know if it did, but it had a tendency to rip easily, but it kept me warm in the cold water all year round. But unlike real shark skin, it didn’t help me swim faster or quieter.
But real shark skin, on the other hand, doesn’t easily tear and roughen human skin if rubbed against it from tail to head. The first shark I touched was a mako we caught in Montauk and when we tied it to the boat I felt its skin and it was almost slippery from head to tail but very rough from tail to head. Before anyone gets mad, we ate the whole shark cut into fillets and grilled with butter and pepper. Fairly good!
But the fact is that shark skin is amazing and is very similar to ray skin, which is a close relative. In fact, long before sandpaper craftsmen used stingrays and sharkskin to smooth wood. I don’t know how long it lasted, but it probably depended on the type of wood that was sanded.
Shark skin is actually made up of microscopic interlocking teeth known as dermal scales, i.e. skin scales. So when they swim through the water, the scales do not create any drag, allowing the shark to move effortlessly through the water. The skin of most sharks is gray regardless of the type of shark, unless it is a bottom feeder that needs to camouflage itself from its prey and other predators. The skin probably protects the shark due to the strength of the skin itself which comes from its thickness and design structure. In fact, the dermal scales of a shark are as hard as granite! wow!
If humans had shark skin, we would probably have far fewer injuries and minor cuts and abrasions would be a thing of the past. In fact, it would be like having a mini chainmail armor. Of course, the interesting part would be that they would all be basically the same color. Imagine that!
So the next time you see a shark in an aquarium or in the ocean, just look at its skin and see if you can see the dermal denticles that are unique to sharks and rays. Probably not, but now you know they’re there.