It’s rare that you get the chance to touch a five-foot bull shark, but then again, you might classify many Sanibel Sea School experiences as “rare.”
Last week while scouring the wrack line for the usual assemblage of shells, seaweed, dead things, and plastic debris, we spotted something a little larger than our normal finds– a freshly dead bull shark about five feet long.
Although not excited that this shark was on the beach rather than swimming freely and stealthily through our waters, we were excited to get such an up-close look at this local predator.
There is a lot to be said for hands-on learning, and with a shark it adds an entirely new dimension to what you can gain from looking at photographs, or even observing through aquarium glass.
Sharks belong to the same group as fish, but upon first glance, you will notice that they don’t appear to have scales like most bony fish. If you rub a shark in the head-to-tail direction, it feels smooth. However, if you drag your fingers in the opposite direction, you will discover a completely different texture–similar to sandpaper.
The texture of a shark’s skin is created by thousands of tiny scales, known as dermal denticles. “Dermal denticles” is literally translated to “tiny skin teeth.” Just like the teeth in a shark’s mouth, they are replaced continually throughout their lifetime, and the shape of the denticles is unique to the species of shark.
Tightly overlapping dermal denticles provide a protective barrier for the shark against both large predators and the smallest of parasites. The grooves and spaces created by dermal denticles also help sharks move silently and swiftly through the water by improving their hydrodynamics—so much so that engineers have mimicked the design in swimsuits and other applications.
Sharks have fascinated, inspired awe in, and been feared by people probably since the beginning of our coexistence, but there is much more to this incredible predator than the jaws!