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Dolphins vs Porpoises – Can they be different?

A Porpoise Head

Dolphins and Porpoises. Are they really that different? Well, while there are many similarities between them, they are also worlds apart from each other. To the naked and untrained eye, most people wouldn’t be able to distinguish the two, because generally they are very much related. However, there are 4 main differences between dolphins and porpoises:

  1. Porpoises are divided into 6 species and sub-species, while dolphins are divided into 40 species.
  2. The average dolphin is longer than the average porpoise.
  3. The mouth and teeth of dolphins and porpoises are very different.
  4. And dolphins and porpoises make sounds at different frequencies.
Dolphins vs Porpoises - Can you tell the difference?
Dolphins vs Porpoises – Can you tell the difference?


Dolphins are best known for their uncanny ability to impress the minds of many with their intelligence and skills. There are about 40 different variations of dolphins, from the Hectors dolphin and short finned pilot, to the spinner and white beak dolphins. Most dolphins inhabit salt water, but there are about 5 species of dolphin that are known to inhabit fresh water: the Amazon River dolphin, the Chinese River dolphin, the Ganges River dolphin, the Franciscan dolphin and the Idus River dollphin. The names of these species of dolphins are related to the waterway that is their habitat. On the other hand, there are 6 types of porpoises that currently reside in the world’s oceans, all belonging to the family, Phococenidae. They include the Burmeister’s Porpoise, Dall’s Porpoise, the Finless Porpoise, the Harbour Porpoise, the Spectacled Porpoise and the rare Vaquita.

A Dolphin Head

Dolphins get their name from the Greek word, Delphus, which means “a fish with a womb.” They are extremely intellegent animals and their friendly appearance and seemingly playful attitudes have made them popular in human culture. Dolphins love to play, especially with each other! At times, they have been known to harass other creatures, such as sea birds and turtles. Dolphins enjoy riding waves and frequently surf coastal swells and the bow waves of boats. They can be seen leaping between the dual bow waves of a moving catamaran. Occasionally, dolphins interact playfully with swimmers. Captive dolphins have been observed in aquariums engaging in complex play behavior, such as creating and moving bubble rings.

Another big difference between dolphins and porpoises is their lengths. Dolphins have a very wide range of lengths and widths, anywhere from 1.2 meters (4 ft) and 40 kilograms (88 lbs) up to 9.5 meters (30 ft) and ten tons, like the killer whale. On the other hand, the average length of a male porpoise is just over 1.5 meters (5 ft) and females are slightly larger with the average length of 1.7 meters (5.5 ft). The average adult porpoise weighs between 61 and 77 kilograms (135-170 lbs).


Due to their small size, porpoises lose body heat more rapidly than dolphins. Their stout shape, which minimizes surface area, may be an adaption to reduce heat loss. Their thick blubber also insulates them from the cold. Their small size also requires them to eat often, rather than depending on fat reserves. Porpoises are rarely held in captivity as they are generally not as capable of adapting to tank life as dolphins.

A Porpoise Head
A Porpoise Head

One of the easiest ways to tell dolphins and porpoises apart is by their mouth and teeth. Dolphins have conical teeth and shorter beaks, while porpoises have flattened, spade shaped teeth. Another difference is that there are more fused neck vertebrae in porpoises than in dolphins, which limits the range of mobility in the porpoise neck. The porpoise even got its name during the medieval times from this noticeable characteristic. They were called “pig fish” from porcus which means pig, and piscus which means fish.

The last way to tell dolphins and porpoises apart is by their sound making. Dolphins vocalize in a range audible to the human ear. However, porpoises vocalize at a much higher range that we simply can’t hear.A recent study showed that porpoises produce high frequency clicks that are restricted to a narrow band of frequencies, while those of a dolphin are not.

You have seen the many key differences between dolphins and porpoises, but there is one thing that you can be sure of when it comes to these two animals: they share the common ability to amaze and enthrall millions who are dazzled by their intellect and unique characteristics. It’s safe to say that these two creatures have been blessed by divine touch.

Blog Post Comments

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17 thoughts on “Dolphins vs Porpoises – Can they be different?

  1. I am collecting sounds of various sea creatures & started wondering if dolphin & porpoise were just different names for the same creature or whether they were actually different creatures. One thing I would like to know that you didn’t address is: do they sound the same, slightly different, or very different from each other?

  2. Hi Tzvi,
    We updated our article and added some information about the different sounds the dolphins and porpoises make. We hope this helps you.

  3. Wow! Such an interesting read! I always thought dolphins and porpoises were the same thing, boy was I wrong!

  4. We live in Santa Cruz California against the Pacific ocean… We have beautiful schools of porpoises I knowing the difference because I have grown up here yet still do not know how to explain what the difference was with facts behind it other then color and size. I am infatuated with dolphins and know they are not here other than our tanks at the Marine sanctuary’s.. Locals giggle and love to listen to tourists with their (excuse me) BS facts, knowing very well that there are no dolphins in these waters I listen to them explain to their family how they ARE dolphins. I being a local know that they are just porpoises and make the joke regularly after correcting them … It’s ok they knew they were fooling you, they do it on ‘porpoise’ ?? and walk away. I wanted to know the difference to help the tourist be able to to pick out the differences. I am most amazed in your article the meaning of the two fishes names. a fish with a womb compare to a pig fish, thank you that will be repeated forever now lol Mesmerized with mermaids and how the two playfully follow in folklore history in every culture … Can’t help but now comprehend how the dolphin gets its beautiful name thank you so much for this education. And out of curiosity since I’m impressed with requests asking why? Have you received many responses? I think that’s awesome way to connect to readers … I never would thought of responding but was impressed enough to do so… Curtsy… Have awesome day/evening

  5. Hi Curtsy,
    Yes, gets lots of questions and responses on this topic. More than I ever thought we would get. It seems like California is the place for porpoises.
    Thanks for your comment.

  6. I understand that there are physical differences between a porpoise and a dolphin. What are some of the behavioral differences between porpoises and dolphins?

  7. Hi William,
    Dolphins and Porpoises are very similar behaviorally. The main difference I know of, dolphins have become popular animals for training in captivity, a situation porpoises do not adapt to well. So this is the biggest difference I know of. If anyone out there know of any other behavioral differences of the two mammals, please let us know.

  8. I now live on Hilton head island SC and see Dolphins (I guess) swimming in the ocean as I walk the beaches and wondered if they were ? Then fresh fish are sold for restaurants and what are those?

  9. Hi Audie, The Fish sold to restaurants are really Mai Mai. Many restaurants call that also, dolphin. Not sure why.

  10. This is of interest to me because the terms seem to be used indiscriminately.
    One wants to know why there are two names for what most people seem to regard as the same thing. I, personally, have never been able to look a porpoise in the mouth to observe the “spade-shaped” teeth while we all have seen the dolphin’s conical teeth thanks to Orca shows and”flipper” TV programs. A clear picture comparing the dentition would be appreciated.

  11. We have a few clearer photos on this updated page. I hope this helps you.

  12. I was curious to know the difference between dolphins and porpoises as we were watching HBO showcase about whales but a lot of them looked like dolphins

  13. Hi there,

    Thanks for the article, just finishing up a cruise of SW FL in a small sailboat, and had an awesome experience with a pod of a couple dozen dolphin(?) a few days ago… A friend pointed out they may have been porpoise, hence my search and reading of your article… Even more convinced now that they were dolphin! They were playing around and under the bow of the boat, a couple even making contact! Cool beyond description.

    Videoed about a third of a twenty min encounter… Attached is a highlight.

  14. We added your video clip to our facebook page if you want to check it out.
    Thank you for the comment!

  15. As a kid I recall hearing both, but as an adult we seem to only hear about dolphin. I was asking my husband the same question when he mentioned that some live in rivers which I had completely forgotten about. Since I’m a south Florida native, naturally the ocean is what usually comes to mind. Thanks so much for the info!

  16. I am a native of Pensacola, Florida and we have always called what I see are Dolphins.
    Other friends and family not from here call them porpoises, which is native to this area?
    Thank you,

  17. Hi Judy,
    In most cases in Florida, it usually dolphins that you see from the shore of Pensacola.

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