Speed Demons: How Do Dolphins Swim?

how do dolphins swim

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Few thoughts are as comforting as imagining a group of dolphins gracefully swimming through crystal clear waters.

Despite the large size and heavy weight they can attain, they seem to effortlessly drift through the seas almost like they are flying or part of a magical ballet while barely moving their bodies.

It’s not just the swimming that’s amazing in these marine mammals, their impressive acrobatics combine strength and elegance in a way that makes it look like something out of a fairytale and not something that a 650 kg / 1433 lbs. animal could possibly do.

Today I will answer the question that has just crossed your mind: how do dolphins swim? How can they move so fast? Is it possible for a dolphin to maybe go backward or upside down?

Let’s dive right in and discover everything there is to know regarding dolphin swimming!

How Do Dolphins Actually Swim?

The body of dolphins has evolved to perfectly allow impeccable and fast swimming despite their large size.

When you first look at a dolphin one of the first things you’ll notice is their super smooth, shiny, hairless skin that would make the best publicity for any skin moisturizer.

This dreamy skin has a very important purpose as it allows the dolphins to neatly glide through the water without creating any resistance or friction. 

The lack of external appendages such as ears, and the shape of its head with a forward-facing snout helps create the streamlined torpedo-shaped body of a dolphin that reliably improves its swimming efficiency.

Two of the most important features that allow dolphins to swim are their strong peduncles and tail flukes.

Let’s start with the peduncles which begin right after the dorsal fin and extend to the tail flukes; the peduncle contains the strongest set of muscles in a dolphin’s body.

With the help of the tail flukes, dolphins move their peduncles in an up and down motion which propels them forward, whereas a fish, for example, moves its body side to side when swimming forward. 

The peduncle of a dolphin determines speed while the tail flukes dictate the direction in which the animal is swimming.

Pectoral flippers also help with steering as does the head. And the dolphin’s dorsal fin provides stability allowing it to stay right side up.

Last but not least, dolphins have a layer of blubber right under their skin which provides buoyancy preventing them from sinking to the bottom despite their large size. 

Can Dolphins Swim Backward?

The only dolphin known to swim backward is the boto also known as the pink dolphin or Amazon river dolphin.

It is unknown why it will sometimes swim like that but this particular dolphin is an amazing gymnast as they have longer flippers that can move independently from one another allowing increased mobility.

Can Dolphins Swim Upside Down?

There are a few species of dolphin that swim upside down for different reasons:

Commerson’s dolphins

Scientists believe this gives them an advantage over their prey as they can swim up on the fish from below trapping them between their body and the surface.


Despite its small eyes, the amazon river dolphin has decent eyesight, but due to its chubby cheeks, this dolphin has a hard time looking down at the river floor when searching for prey.

Swimming upside down allows it to look for food at the bottom of the river. 

Bottlenose dolphin

This species seems to engage in this behavior as a form of play and leisure.

How Fast Can Dolphins Swim?

This is quite a tricky question but to make it simple the top speed for a dolphin swimming near the surface is around 60 km / 37 miles per hour. If the animal is diving deeper its speed could increase a bit. 

However, the reason for the dolphin not swimming faster is not a lack of muscle power as it has the ability to swim much more quickly, though the exact speed is unknown.

The real cause that these cetaceans don’t reach more acceleration is because going faster physically hurts them!

Swimming faster than the aforementioned speed causes a phenomenon called “cavitation”.

What happens is that a bunch of microscopic bubbles form around the tail (which is very sensitive due to all the nerve endings it has) and eventually burst causing pain to the dolphin.

Some animals, such as tuna fish, have been able to “cheat” cavitation because, unlike dolphins who have sensitive tails, these fish have bony tails with no nerve endings so they don’t feel the pain.

In fact, it’s common to find cavitation scarring in the tails of tuna. 

How Do Dolphins Swim So Fast?

For a long time, it was a mystery to scientists how dolphins could swim so fast as it was impossible to make sense of how such a large animal could produce enough energy to move forward at such impressive speeds. 

They seemed to defy all the laws of physics that state that an animal as big and heavy as a dolphin should create turbulence when moving through the water which would in turn create a drag incompatible with the smooth gliding witnessed in dolphins. 

The big secret is their muscular tail and their wing-like tail flukes! These flexible fins generate an impressive lift force that propels the animal forward during both, the upstroke and the downstroke!

Final Thoughts

To sum things up, dolphins have evolved the perfect body for life out at sea!

Every single shape, adaptation, and muscle in their body works together like a swiss watch to ensure the dolphin is the most efficient and hydrodynamic swimmer it can be. 

What amazes me the most is how much we still have to learn about the sublime lives of these marine mammals which seem to really be what dreams are made of with their fairytale looks and impressive adaptations. 

The knowledge currently available regarding these animals is constantly growing and changing as newer, more advanced technology is allowing scientists to better understand their lives and secrets.

One thing is for sure, dolphins will never stop amazing us!