Their skin isn’t like other fish skin! Instead, they’re made up of teeth similar to those in their mouth! In fact, they’re a lot like OUR teeth. Sometimes called “placoid scales,” but better known as “dermal denticles,” they are found all over the body of every shark out there. The dermal denticles have an inner pulp cavity (made up of blood vessels, nerves and other connective tissues) that is covered by a layer of hard dentine, which protects the shark like an armor.
With the skin being tough like armor, it’s no surprise that it’s sometimes very thick! If you ever see a whale shark, here’s a fun fact: their skin there is up to 10 cm (4 in) thick!
Now, remember how we said these scales are streamlined and hydrodynamic? That means their shape decreases the friction of water as the shark swims, thus saving its energy. Hydrodynamic research shows that the scales actually bristle like fur (!!!), pushing water down the shark.
Here are some jawsome pictures of different dermal denticles:
That's it for our Shark Week series!