American Oceans
Difference Between a Dolphin and Shark

What’s the Difference Between a Dolphin and Shark?

Dolphins and sharks are pretty similar looking sea creatures. From the surface of the water, you may even have a hard time determining which is which. 

So what’s the difference between a dolphin and a shark? And how can you tell them apart?

Keep reading to learn more!

Similarities and Differences

Dolphin Blowhole

Though their similar color and shape may confuse you upon first glance, there are many characteristics you can use to help distinguish a dolphin from a shark.

First and foremost, one of the biggest differences between these animals is that they are different kinds of animals.

Specifically, sharks are fish, meaning they have gills, breathe underwater and are cold-blooded. On the other hand, dolphins are mammals, much like humans, meaning they breathe air, are warm-blooded, and nurse their offspring. 

You may know that another defining characteristic of mammals is their ability to give birth to live young. However, interestingly, most sharks give birth to their young as well. 

Although, this does not mean that they are mammals, seeing as they lack the other necessary characteristics to match this description. 

Another difference between these two animals is their behavioral traits. Dolphins are very social animals and travel, live, and hunt in pods. Additionally, they are quite vocal and use sound to communicate and navigate. 

Contrastingly, sharks are not very social and are typically alone. On top of this, they are not capable of making noise in the same way dolphins do. 

Lastly, there are a few physical differences between dolphins and sharks. Perhaps the most well-known difference is that sharks have gills, as mentioned above, while dolphins have blowholes.

Both of these features allow the animals to breathe, however, they look quite different and are located on different parts of the body.

Specifically, gills are located on the side of the shark’s body, near the head, while blowholes are located on the top of the dolphin’s head.

Additionally, the tail fins of these animals are different. Sharks have vertical tail fins, which move side-to-side, while dolphins have horizontal fins, which move up and down. 

Now that we’ve addressed the differences between these animals, let’s talk about a few similarities. 

Of course, sharks and dolphins are both greyish in color. However, other physical similarities they have include a lighter underside, dorsal fins (located on the back), and pectoral fins (located on their sides). 

Also, as mentioned above, both dolphins and (most) sharks give birth to live young. 

Sharks and dolphins also have similar lifespans, usually living about 20-30 years. However, some species of dolphins can live to be up to 40 or older!

How to Tell Dolphins and Sharks Apart

Dorsal fins peak out of water

Though there are many differences we’ve covered, you may be wondering how you can tell dolphins and sharks apart quickly

Despite both sea creatures having dorsal fins, it is possible to distinguish between them if you see a fin above the surface of the water. 

Specifically, the dorsal fins of dolphins are sharp at the tip and arc backwards. On the other hand, the dorsal fins on sharks angle backward slightly and stand up straight in the back.

Similarly, though both animals have pectoral fins, it is possible for sharks to have as many as four. In other words, sharks may have a second fin on the side of their bodies. 

Lastly, as mentioned previously, sharks and dolphins swim differently. Watching the way the animal swims can help you identify which one it is. 

If the tail of the animal seems to be moving up and down, it is likely a dolphin. However, if it is moving back and forth, it is probably a shark.

Final Thoughts

Overall, it is clear to see how different sharks and dolphins are from each other. However, it is understandable why they may be confused from time to time. 

So, the next time you see a grey fin peak out of the water, don’t panic, use your marine animal knowledge to identify if it belongs to a dolphin or a shark!

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