Shark skin's secret germ-fighting power

Shark skin is highly resistant to bacterial colonization because it is covered in microscopic teeth. Instead of flat scales, sharks are covered in 'dermal denticles' that feel like sandpaper to the touch.

The shape and arrangement of these tiny teeth create a surface that makes it extremely difficult for microbes to settle and grow. The patterns disrupt the flow of water and create tiny vortices that essentially 'wash' the shark's skin as it moves.

This is why you never see barnacles, algae, or thick slime on a shark. While whales and turtles are often covered in hitchhikers, the shark remains pristine. The texture is so effective that hospitals are now testing wall coatings modeled after shark skin to prevent the spread of superbugs.

This design also works to make the shark faster. By reducing drag, the denticles allow the animal to move through the water with significantly less noise, helping it ambush prey.

Strangely, these skin-teeth are so similar to the teeth in a shark's mouth that they share the same enamel coating.