Why Can Sharks Swim Quickly Through Water?

Asymmetrical Tail Shape

Unlike most fish, sharks have tails that are not horizontally symmetrical. The top of a shark's tail protrudes further back than the bottom, giving the shark lift while swimming. This asymmetrical tail shape makes the shark "spring" forward at speed, allowing it to move quickly through the water compared to fish with symmetrical tails.

Efficient Propelling Action

Most fish make a single water "ring" that moves backward at the end of their tail's stroke. Sharks, on the other hand, are thought to produce two rings when swimming due to their asymmetrical tail. This unique tail shape leads to a more efficient propelling action, allowing sharks to accelerate and maintain their speed in the water.

Placoid Scales on Skin

Sharks have tiny teeth-like structures called placoid scales on their skin. These scales can be raised to create tiny wells across the surface of the shark's skin, reducing drag. Similar to the dimples on a golf ball that help it move through the air faster, the placoid scales on a shark's skin enable it to move forward faster in the water by decreasing resistance.