What’s Inside A Puffer Fish?
Articles, Blog

What’s Inside A Puffer Fish?

December 9, 2019

If there’s one thing you
know about puffer fish, it’s that they can do this. When aggravated by a predator, they, you know, puff up. Some puffers, like the porcupine fish, become a bona fide spike ball, moving through the water
seemingly out of control. But if you peer inside a puffer, you’ll learn that puffing
up isn’t the only trait that makes these fish one of the most threatening creatures in the sea. Contrary to what it looks like, puffer fish are not like balloons. Because what’s normally
inside them isn’t air. It’s water. Elizabeth Brainerd: What
they do is they actually take water into their mouths
in a big mouthful of water, and then they pump it
down into their stomach. Narrator: That’s Elizabeth Brainerd, a biologist and puffer fish
expert at Brown University. Brainerd: And they do that
anywhere 10 or 15 times, pump, pump, pump, pump, pump, pump, until they inflate completely, and then they hold it and they’ll just be a big, spiny ball. Narrator: And as you might expect, this requires some pretty
sophisticated biology, starting with the stomach. It’s made of dozens of tiny folds, kind of like an accordion. These folds are important because when the stomach fills up with water, it can expand without rupturing. And puffer fish expand a lot. Up to three times their size. That’s like if an average human
man could inflate his waist to a circumference of 3 meters. But there is a drawback
to these amazing skills. Brainerd suspects that
puffer fish stomachs have actually lost the
ability to digest food, which means their intestines
have to do all the work. Brainerd: You know, given
the apparent importance of this defense mechanism, they’ve given up the
advantages of having a stomach where some digestion can start. Narrator: But the stomach? It’s just one of many bizarre
features inside a puffer. For example, they have specialized muscles that you won’t find in most other fish. Some in their mouth, which pump all that
water into their stomach; some in their esophagus,
to seal off their stomach like a drain plug once it’s full; and some in the base of their bellies, which contract to squeeze out water when they’re ready to deflate. But what you won’t find
inside is even more bizarre. Brainerd: There are a couple characters that are really helpful in
their ability to puff up, and one of those is that
they don’t have any ribs, and another one is they
don’t have any pelvis. Narrator: In other words,
puffers are essentially missing bones. And that’s a good thing, because otherwise they’d
get in the way of inflation. In fact, according to Brainerd, if it weren’t for these missing bones, puffer fish would probably have never evolved this way in the first place. And that would be a shame, since puffing up really is a good defense. Consider one old study in which researchers
watched birds go fishing. The birds caught 11 puffer fish, but they dropped nearly half of them because the fish started to inflate. But what’s more surprising is that the birds left with empty beaks might have been the lucky ones. Because puffers have another, more potent defense up their sleeves. Their bodies are laced with a neurotoxin called tetrodotoxin. It’s up to 1,200 times more poisonous than cyanide. So poisonous that one puffer fish can kill 30 adult humans. So poisonous that puffers are reportedly the second most poisonous
vertebrate in the world, which is why it’s also surprising that us humans? We actually eat them. That’s right. In Japan, puffer fish is
actually a delicacy called fugu, which only trained chefs can prepare. And considering that these
fish are basically spike balls filled with poison and we’re still serving
them in restaurants, they must be seriously delicious.


  • Reply Amro December 7, 2019 at 11:10 am


  • Reply Ashleykate Warwick December 7, 2019 at 11:15 am


  • Reply SnoopyDoo December 7, 2019 at 11:38 am

    I always wondered why I occasionally see a stork fall out of the sky.

  • Reply Yougotnomilk December 7, 2019 at 12:53 pm

    Babies if they puff up their bodies don't cope and die due to puffing I had one in my march me tank was about 2 months old and died after bumping into a rock scaring it to puff up and die rip porky puffy

  • Reply How to get Username December 7, 2019 at 1:43 pm

    A carrot?

  • Reply Lizzie's Lukas December 7, 2019 at 1:58 pm

    Nobody :

    Pufferfish : eugh

  • Reply Adam Dairy December 7, 2019 at 2:08 pm

    What's Inside is going to sue you

  • Reply Noodle WAO December 7, 2019 at 2:44 pm

    Title: What's Inside a Puffer Fish?
    Me, an intellectual: A carrot.

  • Reply spiker-wave December 7, 2019 at 3:00 pm

    When they are caught by birds, do the puff up inhaling air instead?

  • Reply AliveC4T December 7, 2019 at 3:27 pm

    Is this science insider or bullshit insider? In Japan farmed puffer fish have neither spikes nor any poison. Educate yourself before making a video, instead of spreading misinformation…

  • Reply randomize December 7, 2019 at 4:40 pm

    I thought carrots were inside pufferfish…

  • Reply Inazarab December 7, 2019 at 5:15 pm

    They're not delicious.

  • Reply Nafeesa Hussain December 7, 2019 at 5:45 pm

    Science insider: Uses metric

    Me: confused as an uneducated American

  • Reply Shiree Espinoza December 7, 2019 at 5:47 pm

    Fun fact; as a kid I loved the pufferfish. Read a book about dangerous animals and it was in there. As an adult I still own that book and do cute voices to puffys at the aquarium. :3

  • Reply ButtonWalls December 7, 2019 at 5:57 pm


  • Reply You Have Been Bruhe'd December 7, 2019 at 6:30 pm

    Eugh ugh

  • Reply Nate g the pigeon lord December 7, 2019 at 6:44 pm


  • Reply CrazyAimbot December 7, 2019 at 8:35 pm

    I think we've all watched the video of the pufferfish eating a carrot.

  • Reply youll get your rent when you fix this damn door! December 7, 2019 at 8:51 pm

    Science Insider: lets make a ‘what’s inside a puffer fish’ video.

    What’s Inside: aM i A jOkE tO yOu?

  • Reply Yusuf Erdoğan December 7, 2019 at 9:04 pm

    ? ? eugh

  • Reply Ervin Z December 7, 2019 at 9:11 pm

    So how exactly do you become a puffer fish expert and why???

  • Reply SnesBoy December 7, 2019 at 9:16 pm

    æúh üh

  • Reply DanielTroy Prod. December 7, 2019 at 10:50 pm


  • Reply Daneil - Roblox December 7, 2019 at 11:43 pm


  • Reply MysteriousPT December 8, 2019 at 12:05 am

    C A R R O T

  • Reply Mr Spectacals December 8, 2019 at 12:13 am

    ?? Augh

  • Reply Holdin McGroin December 8, 2019 at 12:30 am


  • Reply bark- I December 8, 2019 at 12:41 am

    Whats the most poisonous vertebrae in the world

  • Reply Caio Henrique December 8, 2019 at 1:04 am


  • Reply Nathaniel Clay December 8, 2019 at 1:28 am

    Only reason why i'm watching this is because I saw a gagging puffer fish meme

  • Reply Kiwi Dew December 8, 2019 at 1:34 am



    -puffer fish

  • Reply Cammey Le December 8, 2019 at 1:40 am


  • Reply Marina McKinley December 8, 2019 at 1:49 am

    This is such a weird meme and everyone is getting on board. They risk death if they puff up out of water, so all I can think about is how sad that viral video is. Those are death knells. In aquaculture, this is one of the first things you learn and sometimes it is learned the hard way. I won't even net my puffer out of the water because of this risk.

  • Reply Kay Swift December 8, 2019 at 2:00 am

    At 0. 43 says the puffer fish take water into their mouth to puff up. But i saw their puffed up without water just in my palm for several times…

  • Reply Derp Noodle December 8, 2019 at 2:11 am


  • Reply Virginia Butler December 8, 2019 at 2:39 am

    Puff puff

  • Reply Dragon Beast December 8, 2019 at 2:40 am


  • Reply NeoXenoZ December 8, 2019 at 2:53 am

    Give a pufferfish a carrot and it will augh

  • Reply Master Frown Is The best Living Thing December 8, 2019 at 3:10 am

    i like pufferfish moan

  • Reply ғʀᴇɴᴄʜ ғʀɪᴇs December 8, 2019 at 3:14 am

    Spongebob: Mrs. Puff are you ok?

  • Reply Etceterotic December 8, 2019 at 3:16 am

    Well, I’d die if I eat any fish. Puffer fish aren’t special.

    In this house, we don’t discriminate.

  • Reply mortgage 2001 December 8, 2019 at 3:27 am

    No. It tastes just like. FISH

  • Reply Dee B December 8, 2019 at 4:01 am

    Japanese: Hippity hoppity this Puffer Fish is now gonna be a Sushi.

  • Reply Ndodana Chuma December 8, 2019 at 4:13 am

    Question! Why do they puff up when we accidentaly hook them with a fishing hook??outside water????where ,dnt lie sister they use air aswell to puff up

  • Reply Common Sense December 8, 2019 at 4:21 am

    Those animated eyes are so freakin adorable

  • Reply GoldDropper December 8, 2019 at 4:24 am

    50% The fact Japanese eat them
    50% Pufferfish eating carrot meme

  • Reply Mior December 8, 2019 at 4:28 am

    So you're telling me that their stomach isn't filled with Carrots and they don't say AEUGH?
    Press F

  • Reply Rathi SSJ December 8, 2019 at 4:28 am

    Human: ??
    Puffer: ?

  • Reply YouTube Logo December 8, 2019 at 4:31 am

    Inside a puffer fish is air

  • Reply Goku Vegeta December 8, 2019 at 4:39 am

    Elizabeth BraiNerd!
    Mind blown!

  • Reply Coby Dickes December 8, 2019 at 4:59 am

    All I can say is æugh

  • Reply HaHarmageddonTV December 8, 2019 at 5:01 am


  • Reply The DARK Lover December 8, 2019 at 5:18 am

    40% of comments = Japanese people eats puffer fish

    30% of comments= eugh
    30% of comments = puffer fish eats carrot meme

  • Reply Dracodracarys 233 December 8, 2019 at 5:20 am

    cue carrot memes

  • Reply ThaTricksta December 8, 2019 at 5:21 am

    Y’all know why they made this video

  • Reply Woojin Park December 8, 2019 at 5:54 am

    This video was interesting until it showed the Japanese rising star flag. Its as bad as the Nazi Swastika. Be better!!

  • Reply Khanya Maweni December 8, 2019 at 5:55 am

    Mrs Puff from Spongebob

  • Reply The Plush Productions! TPP December 8, 2019 at 5:59 am


  • Reply itzNova December 8, 2019 at 6:09 am

    0:51 her name itself suggests she's a nerd ?

  • Reply ATLATL December 8, 2019 at 6:10 am


  • Reply Kdreads December 8, 2019 at 6:27 am


  • Reply Bigatex 720 December 8, 2019 at 6:37 am

    ?? ÆUGH

  • Reply Mr.DarkBright December 8, 2019 at 6:39 am

    Aeugh ??

  • Reply Sergio Nazario December 8, 2019 at 6:49 am

    When aggravated by my stress and thoughts I “Puff Up” ?☁️

  • Reply Ma Jann December 8, 2019 at 7:03 am

    Who come after meme????

  • Reply Puck Chang December 8, 2019 at 7:26 am

    you can also make lamps with googly eyes out of them! or glu some shells on their back and make a little sailing ship!

    and so come to the conclusion that this world must have lost its mind

  • Reply NateTheGreat December 8, 2019 at 7:49 am


  • Reply Starfydusty December 8, 2019 at 8:11 am

    Supposedly, fried fugu is some of the best-tasting fish out there. I had a chance to try it while I was in Japan, but I backed out.

  • Reply SkullFrosted Jr December 8, 2019 at 8:36 am


  • Reply Këįn Jävlą Ŕęëvêß December 8, 2019 at 9:22 am

    What's inside a Puffer Fish?

  • Reply Milan Trkulja December 8, 2019 at 9:27 am

    It's not air it's water .
    No shit Sherlock.

  • Reply Rayhan S December 8, 2019 at 9:42 am

    Spiked, poisonous, ugly
    A fish who really don't wanna get eaten
    Japanese people : yuum yuum

  • Reply Bong Neng December 8, 2019 at 10:04 am


  • Reply RyderKun Animations December 8, 2019 at 10:07 am


  • Reply where is my shoes December 8, 2019 at 10:16 am

    Inside of puffer fish are carrots

  • Reply Jadden December 8, 2019 at 10:49 am

    Sooo poisonous & people will eat almost anything nowadays..

  • Reply edboss December 8, 2019 at 11:08 am


  • Reply Klent Galimbas December 8, 2019 at 11:59 am

    Remembering my childhood. My mom sometimes cooked this with coconut milk. Sometimes I hate this fish since it always eat my fishing hook, it is so hard to get that I have to cut the hook.

  • Reply Ashton S. December 8, 2019 at 12:24 pm

    eats carrot EUGH

  • Reply Spsuperstar December 8, 2019 at 12:41 pm

    SpongeBob: Mrs Pufferfish, is that you?

  • Reply Steven Salgado December 8, 2019 at 12:48 pm

    But when i go fishing somtimes there not inflated in the water but when them out they inflate are the sucking up air?

  • Reply Summy December 8, 2019 at 1:05 pm

    "Eugh aughhh"- phish

  • Reply Toxik.Biohazard December 8, 2019 at 1:39 pm

    What's inside a Pufferfish?


  • Reply %??? December 8, 2019 at 1:41 pm

    There are carrots inside it

  • Reply Snickerdoodle December 8, 2019 at 1:44 pm

    they eat carrot?

  • Reply Tommy Sprangs December 8, 2019 at 1:49 pm

    how do they puff up out of water then

  • Reply Walid Saripada December 8, 2019 at 2:05 pm

    That puffer fish its hungry now he want to eat carrot??

  • Reply Juha B December 8, 2019 at 2:16 pm

    For a channel that teaches covers knowledge and informations, I'm surprized to see that the video makers don't know the meaning of Japanes rising sun flag how offensive it is to see the sign to the people from certain regions of Asia.

  • Reply SleepLess December 8, 2019 at 2:23 pm

    Carrot be like:

  • Reply Agent 2254 December 8, 2019 at 2:37 pm


  • Reply KYOUSHA December 8, 2019 at 2:55 pm


  • Reply PlasmaBlix December 8, 2019 at 2:59 pm


  • Reply Johnny December 8, 2019 at 3:02 pm

    When the pufferfish said "ÆÜGH"

    I felt that

  • Reply r2012j December 8, 2019 at 3:13 pm

    Elizabeth brain nerd, self explanatory!!

  • Reply Metal Man December 8, 2019 at 3:13 pm

    No mention of carrots? Disappointing.

  • Reply Maki Bliss December 8, 2019 at 3:15 pm

    No it's carrots

  • Reply Envy December 8, 2019 at 3:48 pm

    ?? augh

  • Reply AmaDaX December 8, 2019 at 4:34 pm

    Thats easy cmon.

    Puffer fish has a carrot inside

  • Reply Arnold J Rimmer BSC December 8, 2019 at 11:19 pm

    Obviously you will grow up to be intelligent if you have the words "brain" and "nerd" in your surname

  • Reply anthony olavarria December 9, 2019 at 2:55 am

    æügh -eügh

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