Why Fish Can Drink Salt Water And We Can’t
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Why Fish Can Drink Salt Water And We Can’t

August 16, 2019

Salt is everywhere on our planet, but some
animals evolved to live in it while, others didn’t; what happened there? What caused this
split? Sup salty dogs, thanks for watching DNews,
I’m Trace. Water is everywhere and is one of the main reasons life was able to evolve
on Earth. It’s pretty great. Salt is also everywhere. Salt and water together, make
up most of the water on our planet and it’s a major component of the beginning of life
as we know it! Organisms need salt to survive. Salt draws
water out of cells in process called osmosis. Osmosis is the tendency of water to flow across
a membrane to balance salinity. Essentially, nature wants to make sure there’s a balanced
level of salt everywhere. This is why if you drink saltwater you can die of dehydration
— the water-salt balance gets out of whack and water gets pulled out of your cells. It’s
pretty serious. And yet, as boney fish moved from a salty
sea into freshwater (or sweetwater), they had to eat salts to maintain that salt-water
balance. They still do this today, urinating any excess salt — sometimes up to a third
of their body weight a day. We do this too, which is why we crave (and love) SALT. But
this brings us to the big question — if saltwater fish are drinking saltwater constantly, how
do they avoid dehydration due to osmosis?! Well, there are two answers. One comes built
in. The gills of some saltwater species, like the flatfish: turbot, have adapted to carry
more of a special enzyme called “gill Na+/K+ ATPase.” This allows their gills to leach
salt from their bodies back into the ocean. Without this adaptation they’d die because
of that high salinity. But, some species of eel, salmon, bass, and
flounder have adaptations that let them move between fresh and saltwater! Species which
can survive in a variety of salinities are referred to as euryhaline; some even actively
adapt their gills or their kidneys… There are a lot of species osmoregulating in a lot
of different ways. This is a great example of how evolution solves a problem along many
different paths, something scientists call convergent evolution! SO AWESOME. So, lemme give you a couple examples: anadromous
fish, are born in freshwater and live there for months before they make for saltwater.
In Atlantic Salmon, an enzyme called type 2 deiodinase is produced in response to the
longer daylight hours in spring. Puberty ain’t just weird for humans. This enzyme alters
the salmon’s gills, initiating osmoregulation so they can safely swim into salty water!
This is reversed when they return to rivers and streams to breed and start the process
with thier own lil’ salmons. And a 2013 study in Molecular & Cellular Proteomics,
detailed how a DIFFERENT adaptation evolved in tilapia. When placed into salted water
gradually, the researchers found tilapia gills adapted, producing a specialized protein called
NDRG1. This let the tilapia survive in a saline environment — as long as they had time to
slowly adapt. A lot fish evolution has happened in the last
400 million years. Fish have spread into pretty much every water-based environment on the
planet. After the Great Dying 250 million years ago which wiped out 95 percent of all
marine species, evolution had to figure out how to osmoregulate again. Through an assortment
of convergent evolutionary adaptations FRESHWATER fish repopulated the oceans — learning to
deal with the super-salty water. Eventually, they made it to land as well, when a fish
named eusthenopteron evolved into amphibians — and tetrapods — like you and me! Without
salt, and being able to regulate it, life as we know it wouldn’t exist. Evolution is the best.


  • Reply CoconutMan1528 April 9, 2016 at 12:44 am

    These DNews advertisement plugs are legendary. Well played DNews. Well played.

  • Reply yeah April 9, 2016 at 1:39 pm

    What are Israel's violation of international law??

  • Reply jose garcia April 9, 2016 at 2:31 pm

    Hey I have a question. Can animal taste their foods like us?

  • Reply Saint of Bacon April 9, 2016 at 5:20 pm

    Why are there catfish species literally everywhere?

  • Reply Selin April 9, 2016 at 9:47 pm

    I hope Trace never leaves DNews

  • Reply oscarg510 April 10, 2016 at 12:18 am

    Let's boycott this series until they do away with the 30 second mandatory commercials!

  • Reply 8elhaj April 10, 2016 at 4:15 am

    Adaptation not equal to evolution.
    Find the missing links before you talking about evolution, it literally became just a dogma like religion.

  • Reply Trace April 10, 2016 at 4:35 am

    oh my god i have not found another person named Trace in my entire life

  • Reply Smith Anderso April 10, 2016 at 4:41 am

    Hey Trace…make video about Cloud.Seeding

  • Reply shriram nayak April 10, 2016 at 6:59 am

    why can't we purify salt water and drink

  • Reply Yazan Adnan April 10, 2016 at 2:52 pm

    Cuz fish are dumb

  • Reply Awakened IntoFreedom April 10, 2016 at 4:04 pm

    moonlight is cold you liars moonlight is cold I want my science award the Moon emits it's own light and it's cold I CAN PROVE THIS come on Trace any of you that have a curious science mind give me a chance to debate any of your best scientists the Moon emits it's own cold light.

  • Reply Travis g April 10, 2016 at 5:04 pm

    then how do mammals who live in salt water deal with only having salt water to drink?

  • Reply Niskinatorn April 10, 2016 at 9:39 pm

    Remember to come back here every day so that you can get more D… news.

  • Reply micahve April 11, 2016 at 1:26 pm

    was this an ad for animal planet??? if so AWSOM!!!!

  • Reply Timothy Schuster April 11, 2016 at 9:15 pm

    What do whales and dolphins do???

  • Reply andre andes April 11, 2016 at 10:54 pm

    I its not natural selection than its not true.

  • Reply Ahsan Siddiqui April 12, 2016 at 12:00 am

    Dnews Can you explain Salt therapy that some companies are offering they say that it is good for you and charge a hefty sum for it. Is it just a scam. or is it real.

  • Reply Opinionated Misogynist April 12, 2016 at 1:16 am

    Dat shameless advertisement doe.

  • Reply Ben Med April 12, 2016 at 3:55 pm

    at pase lol..

  • Reply askquestionsplz April 12, 2016 at 4:17 pm

    whenever i hear quotes on timelines from 10k years ago or longer, i roll my eyes. it is all speculation and mostly BS. like dinosaurs for example.. carbon date a bone without letting the dater know what it is and the date is within 100k years. tell them it's a dinosaur fossil and they immediately date it as millions of years. to assume we know the timeline of anything just demonstrates humanities blind faith in bullshit.

  • Reply SirEvilestDeath April 12, 2016 at 5:14 pm

    Fish can and I can't? That makes me so salty!

  • Reply bot in action April 12, 2016 at 10:42 pm

    Salt water tastes better than clean water

  • Reply Thee Quinther April 12, 2016 at 10:53 pm

    S E L L O U T

  • Reply Richard Taylor April 12, 2016 at 11:13 pm

    What stops different species from breeding with each other for example dogs and cats rhinos and elephant or a human and mouse I've always wondered this

  • Reply Saul April 13, 2016 at 9:07 am


  • Reply aboubrad April 15, 2016 at 12:34 pm

    can you do a video on how gills work? how do they extract and isolate oxygen from seawater? thank you for your kind attention

  • Reply Peyton Lovas April 17, 2016 at 1:03 am

    that gill pastes name is Gill Nakat paste

  • Reply wulfrich April 17, 2016 at 5:59 pm

    I like your shirt.

  • Reply Saiyan Cragus April 20, 2016 at 9:12 pm

    Looking for Osmosis Jones references and shout outs!

  • Reply suDz April 25, 2016 at 11:42 am

    Because they were born in it, molded by it. They didn't see fresh water until they were already Big Fishes !!

  • Reply Dom Trussardi May 7, 2016 at 9:26 am

    Fish thumbnail for the win.

  • Reply podcastbard May 19, 2016 at 6:09 pm

    What bout baking soda and water? Is there salt in that?

  • Reply RICHARD HUDMAN June 14, 2016 at 10:25 pm

    micro evolution is real, not macro

  • Reply Dennis Totman June 26, 2016 at 3:27 pm

    Evolution? Rubbish. Try adaptation.

  • Reply JTS21 •Jeff• August 6, 2016 at 6:09 am

    Im eating salt right now😳

  • Reply Ryan Harrison November 2, 2016 at 5:36 pm

    love that the link was in the video on mobile

  • Reply Apoc Sentinel November 2, 2016 at 11:24 pm

    lol the way the personifies evolution is cringy

  • Reply Dah Dream November 2, 2016 at 11:29 pm

    Ap bio IS USEFUL <3

  • Reply Mitchell Turcot November 3, 2016 at 2:56 am

    such pun many no

  • Reply Royalty Kennels November 3, 2016 at 6:10 am

    who else thinks trace is cute? 😛 i can listen to his nerdy ass talk all day 💅. 💋💋💋💋💋

  • Reply Whole Food Plant-Based Man November 3, 2016 at 4:15 pm

    Please do more biological videos like this.

  • Reply Daniel Madigan November 3, 2016 at 9:21 pm

    Why is this important….

  • Reply Closing the Loop November 3, 2016 at 9:29 pm

    Evolution is the best! I worship evolution. I think evolution is God. God is brilliant. He sent his son to die for us. He is the epitome of good. I love God

  • Reply GDI December 8, 2016 at 4:13 am

    88 religiously indoctrinated people can't accept facts

  • Reply Lucinda Ash December 9, 2016 at 5:36 am

    I drank salt water, I am crying am i going to die!?!?!? i am so scared i only drank 3 swallow of it! i am so scared!

  • Reply Justin Howle January 2, 2017 at 1:43 am

    God is great:-)

  • Reply Dalton Carver January 2, 2017 at 1:54 am

    7.8 out of 10 – Too much water

  • Reply fikri hisyam January 29, 2017 at 5:20 am

    so do you mean all tilapia can survive in salt water?

  • Reply Bob John March 6, 2017 at 6:00 pm

    why only platypuses lay eggs and not other mammals?

  • Reply Mackenzie Abts March 15, 2017 at 3:48 am

    Trace is probably my fav member of this channel tbh.

  • Reply Jefferson Diaz March 29, 2017 at 5:39 pm

    Evolution is still a theory even if it's talked about as fact. While I do believe there is a small amount of evolution that exist there is no concrete evidence that proves it

  • Reply Mánuel Kiatoko April 3, 2017 at 8:05 pm

    Funny how fish are already in the ocean full of salt but they still need some salt when being cooked.

  • Reply ilam buduri April 12, 2017 at 5:50 am

    evolution. when asked about it they say millions of years. we aint have millions years of life spawn. evolution is so wrong. 0+0=1

  • Reply efs83dws April 23, 2017 at 5:23 am

    No answers. Just "oh evolution is so wonderful."

  • Reply Solomon Muya May 5, 2017 at 10:37 am

    It seems this guy evolved from a fish.

  • Reply Ellie Xox May 7, 2017 at 9:07 pm

    I have drank it ITS YUCKY

  • Reply Ellie Xox May 7, 2017 at 9:07 pm


  • Reply killer gamer May 8, 2017 at 5:07 pm


  • Reply Icy Shadows May 27, 2017 at 8:11 am

    We can't drink salt water? What, never heard of Gatorade?

  • Reply Ddd Bbb May 30, 2017 at 1:11 pm

    evolution is a hoax

  • Reply GBE Smokes July 5, 2017 at 10:07 pm

    why did dnews change it's name?

  • Reply The Normal Theorist July 17, 2017 at 4:09 am

    Ive licked a fish by accident.

  • Reply Wowzer August 1, 2017 at 8:14 pm

    I've drank salt water..

  • Reply tancheeken August 7, 2017 at 3:41 pm

    I would argue that it is designed. The salt would have killed all the sea creatures before they can adapt.

  • Reply divcrfc August 8, 2017 at 3:41 pm

    Evolution is false God is real

  • Reply Aria Foregin August 20, 2017 at 3:12 pm

    Actually, we CAN and should drink sea water! Isotonized of course and not in big quantities, but it contains a lot of nutrients to our cells and a lot of elements of the periodic table, also, it's very similar to our blood and it can heal alot of diseases/illnesses and end whith desnutrition!

  • Reply snow man September 23, 2017 at 12:42 pm

    "Evolved" LooooooooL …….. Jesus still love you

  • Reply Anel Goat October 11, 2017 at 1:01 am

    I drink ocean water all the time!

  • Reply KEVIN tboy November 8, 2017 at 12:53 am

    Like where did study this
    and how
    are u even explaining it in school I would be stuttering

  • Reply Larry Medina November 27, 2017 at 12:13 am

    What about orca whales.

  • Reply Vicente lopez rodriguez December 17, 2017 at 12:19 pm

    because we are smartest.

  • Reply John Castillo December 25, 2017 at 10:25 am

    Can we stop talking as if evolution is a fact? I mean it's still just a theory, you could do a video like this without saying "it's how they evolved" lol

  • Reply Fusion Tricycle January 4, 2018 at 1:40 pm

    Look for that one young-earther that doesn't believe in evolution.

  • Reply Uncut Fishing January 7, 2018 at 2:30 pm

    Actually, newly spawn Atlantic salmon live in rivers not for "months", but for 2-3 years before migrating to the ocean or the nearby sea, sea trout stay for 2-4 years, etc. Fish grow slower and live longer than many think they do.

  • Reply Midnight Pronghorn January 10, 2018 at 5:44 am

    Ugh. I’m watching in 2018 and saw the 2016 date. I still thought “ really? Just a year ago?”

  • Reply Madrenna Griffith February 24, 2018 at 6:52 pm

    I think you mean CREATION is the BEST!!!

  • Reply Emmillyy March 6, 2018 at 3:04 am

    "salt is everywhere on our planet…."

    he's talking to you, salty ass

  • Reply Abdul 666 March 15, 2018 at 5:32 pm

    Maybe (sea) salt water is fish whale other species urine thats why they can more toleration

  • Reply err0r March 25, 2018 at 1:20 am

    I like to eat salt, the pure and amazing delicious rock.

  • Reply Zakaria Hassan Mohamed April 2, 2018 at 3:23 pm

    Nature wants? Nature has as much consciousness as my shoes. I think you meant God.

  • Reply Ocean King April 10, 2018 at 5:14 pm


  • Reply Ocean King April 10, 2018 at 5:14 pm

    that was weid

  • Reply K S April 13, 2018 at 9:18 am

    I don't think I've ever watched a video on this channel that doesn't reference evolution a bunch of times…try to stick to the facts please. You don't need to bring up a theory to explain how fish work. And please don't talk about evolution like it's a fact.

  • Reply The Dishonored Coward April 16, 2018 at 5:45 pm

    This is a little more relatable then the last video.

  • Reply Juan Marcus Lopez May 7, 2018 at 7:11 am


  • Reply gwenhidwy May 11, 2018 at 4:07 am

    The fish is pronounced tur-bo

  • Reply Sinisterene June 12, 2018 at 6:13 pm

    But question how evolution affected the animals known as humans and you're a waycist

  • Reply Gillian Patton July 6, 2018 at 10:17 pm

    I got an idea that will save our drought problem and it involves CRISPER! Anyone want to guess?

  • Reply Content Brony August 20, 2018 at 3:28 am

    Plankton reduces pollution/carbon dioxide less fish mean less pollution win win

  • Reply Nerion, Espy Of Wolves August 20, 2018 at 6:53 pm

    they dont get dehydrated with all the salt.

  • Reply gonzalo moreno andonaegui September 7, 2018 at 5:19 am

    Great video, I have a question: How does whale sharks and manta rays breathe and filter plankton with their gills, and how do they swallow the plankton ?

  • Reply Larde T September 24, 2018 at 10:33 am

    Hahaha buwad mana ang katung isda nga flat,lami kaayo

  • Reply Slices of SIB December 13, 2018 at 7:06 am

    You wont DIE from drinking salt water

  • Reply Joey Worley February 15, 2019 at 4:52 am

    Evolution is a theory. Not proven. So speak of it as it is and not as what you think.

  • Reply Martini7771981 February 20, 2019 at 10:03 pm

    Nothing evolved .Water on the beggiing was not salty it was fresh water and slowly it bacame salty .Evolution is not a intelligent person to figure something and nothing we observe did not appeared on this planet by the chance without intelligence or creator .Animals and sea creatures simply adopted to changable conditions , not evolved .They like to abuse this word frequently . It is not observable science as any animal has never changed kind . Animals multiply according to their kind , the same with humans and this is observable science that can be presented everyday withouts myhts about magical millions and billions of years .If not believe me please give me one observable example for evolution change of kind . Historians still argue about facts from the second WORLD WAR and that was just over 70 years ago , no one knows what had happened even few thousands years ago never mind even single milion years . We have got great scientific theories, aaumptions but ultimately these are not FACTS. It is not evolution it is adoptation . Fish stays fish all day and all year long and it does not morph into anything else . It was fish right from the beggining so was the cat dog etc , please give me one observable example for evolution change of kind one example will be enough one observable example not allegded one …………..Please do not say that something happened millions of years ago but we can not see it today …please be serious

  • Reply Blad Romero March 9, 2019 at 4:10 am

    Evolution does not exist…

  • Reply jhunzio dionzkie March 30, 2019 at 3:56 am

    Intelligent designs everywhere.

  • Reply The Most Interesting Man On Youtube June 15, 2019 at 5:39 pm

    Nah Evolution is Retarded , if it was the best then it would've gave us the ability of drinking Salt Water that would've solved a lot of problems

  • Reply get out of my life channel August 13, 2019 at 1:44 am

    Ask me how i know fools

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