Question: how does sharks swim quickly

Emilia McAllister-Jepps answered on 8 Nov 2016:

Hi, interesting question!

Sharks can swim fast for a number of reasons, first and foremost, they have evolved over thousands of years and their bodies have adapted to suit the environment in which they live.

A couple of adaptations that allow them to swim fast are their skin, their fins/tail and their gills. So what about these things allows them to swim fast?

On appearance a sharks skin is smooth in one direction and rough in the other, having smooth skin in the direction in which they swim aids with hydrodynamics and reduces resistance through the water. This type of skin is called Placoid scales.

Sharks are seriously strong, so this helps them swim fast, but the main source of propulsion is the tail. The tail of a shark is not symmetrical like other fish, the top fin of the tail is longer than the bottom and also slightly slanted, this helps to generate lift in the water, which helps the shark not to sink. Whilst most fish swing their tail from side to side, there has been research into the pattern of a sharks swing. The research showed that whilst the tail does move from side to side, there is a an added thrust mid-swing which comes from the tail stiffening. This extra thrust helps to move the shark forward.

Finally, if a shark doesn’t swim it cannot breathe. So the faster the shark swims the more effectively it can take in oxygen and release waste products.

Do you think there is anything else that could help a shark to swim fast?