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Why Are Marine Mammals So Big?

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Marine mammals are famously large, but why is that? And is there a polar bear-sized sea otter in our future? Check out PBS Eons!: https://www.youtube.com/watch?v=_OSRKtT_9vw Hosted by: Olivia Gordon Head to https://scishowfinds.com/ for hand selected artifacts of the universe! ---------- Support SciShow by becoming a patron on Patreon: https://www.patreon.com/scishow ---------- Dooblydoo thanks go to the following Patreon supporters: Jerry Perez, Lazarus G, Sam Lutfi, Kevin Knupp, Nicholas Smith, D.A. Noe, alexander wadsworth, سلطان الخليفي, Piya Shedden, KatieMarie Magnone, Scott Satovsky Jr, Charles Southerland, Bader AlGhamdi, James Harshaw, Patrick D. Ashmore, Candy, Tim Curwick, charles george, Saul, Mark Terrio-Cameron, Viraansh Bhanushali. Kevin Bealer, Philippe von Bergen, Chris Peters, Justin Lentz ---------- Looking for SciShow elsewhere on the internet? Facebook: http://www.facebook.com/scishow Twitter: http://www.twitter.com/scishow Tumblr: http://scishow.tumblr.com Instagram: http://instagram.com/thescishow ---------- Sources: https://news.stanford.edu/2018/03/26/aquatic-mammals-need-big-not-big/ http://www.pnas.org/cgi/doi/10.1073/pnas.1712629115 https://www.nationalgeographic.com/animals/mammals/b/blue-whale/ https://www.smithsonianmag.com/science-nature/how-did-whales-evolve-73276956/ http://www.uvm.edu/~dstratto/bcor102/readings/01_phylogenetics.pdf https://www.nature.com/articles/ng.3198 http://hyperphysics.phy-astr.gsu.edu/hbase/Tables/thrcn.html http://www.jstor.org/stable/10.1086/303400 Media Sources: https://commons.wikimedia.org/wiki/File:Indohyus_BW.jpg https://commons.wikimedia.org/wiki/File:Puijila_darwini_(fossil).jpg https://commons.wikimedia.org/wiki/File:Tethytheria_2.jpg https://commons.wikimedia.org/wiki/File:Mustela_nivalis_-British_Wildlife_Centre-4.jpg https://commons.wikimedia.org/wiki/File:Humpback_whale_by_Christopher_Michel.jpg https://commons.wikimedia.org/wiki/File:Manatee_and_fishes_underwater_photo.jpg https://commons.wikimedia.org/wiki/File:Lev-Beh-Ziz.jpg https://commons.wikimedia.org/wiki/File:Dark_Dolphin.jpg https://commons.wikimedia.org/wiki/File:London_MMB_%C2%BB189_Natural_History_Museum.jpg https://commons.wikimedia.org/wiki/File:Sea_otters_holding_hands,_cropped.jpg
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Text Comments (711)
Nafrost (1 month ago)
what about dolphins?
Darragh Collins (1 month ago)
hang on. Don't sea otters live in shallower water where it's warmer and kelp is more accessible. Maybe they don't need to grow cause it's not as cold.
Haiti LeBlanc (1 month ago)
Definitely terrifying
Pixel Fox (2 months ago)
2:16 Sea otters may be the "odd-balls" because of that fur. The vast majority of marine mammals have little to no fur. They rely on their blubber and size to keep them warm in the chilly water. Sea otters went a different route -- they have literally the densest fur in the animal kingdom, at 150,000 strands per centimeter square, or 1 million strands per square inch. In comparison, chinchillas, with the densest fur of any terrestrial mammal (so dense that fleas and ticks can't penetrate it!) have "only" a third of that -- 50,000 per cm2. Sea otter fur is so thick that, even after spending hours and hours eating and playing and grooming and sleeping in the water, their skin stays completely dry. So they don't need the massive amounts of blubber and fat to keep them warm. Ergo, a marine mammal that's "trim", as the video put it.
seatbelttruck (3 months ago)
Adorable and terrifying aren't necessarily mutually exclusive.
Sellyei (3 months ago)
Otters big as Poar bears.... ... well.. ... WELCOME TO JURRASIC PARK!!!
Le Quasar (3 months ago)
I just use a balance to weight myself... I must be a marine mammal...
Crispynugget (3 months ago)
the mismatched earrings is killing me
CircleTheSkies (3 months ago)
With otters, it might be that their fur is better at heat-retention; it's renowned as the thickest among mammals - so they might've stumbled on an alternative to the 500kg "optimal size". They also do spend some time on land - not a whole lot, but it gives them a bit of flexibility in avoiding orcas and the like.
Old Soul (3 months ago)
She looks like Amy from the Big Bang Theory.
Old Soul (3 months ago)
So land animals would have been bigger if they were in water?
Timmy Teaches (4 months ago)
She's gotten so much better at presenting. Used to be you could hear the anxiety in her voice and the tone and nuances were offputting to a degree. But now the camerashy-ness is all but gone completely and that little nervous inflection where she would end every sentence with a low guttural drone is nearly unnoticeable now. Very good. Keep on making the effort to improve and before you know it you'll be speaking at a professional level.
neostake (4 months ago)
Were you on the Big Bang theory?
Cecilia Benevides (4 months ago)
otterly terrifying
Rogred (4 months ago)
Wow, who's this beauty?
Juan Suarez (4 months ago)
No animal has ever been recorded having a baby of a different species it’s always a slight variation of the same animal. Just like Bible teaches us. Evolution is a man made religion. Praise be a Lord Jesus Christ.
9kingmax (4 months ago)
You forgot about mammals fifth entrance into the water, marine sloths of ancient Peru! https://en.wikipedia.org/wiki/Thalassocnus
Jason Wood (4 months ago)
A sea otter the size of a polar bear- but round like a balloon animal
Dumble Door (4 months ago)
Interesting talk, thanks. I would have liked some more stuff about the human aquatic ancestor, but if the 500kg rule is true, I guess our aquatic ape ancestors were as big as some of the fattest people alive today, which is interesting 😀🙊🙉🙈
beefgoat (4 months ago)
In other words, we (mammals) rock!
Titus (4 months ago)
here's a weird thing about evolution there were animals that evolved legs to walk on land and for some reason evolved to go back and live in the ocean
Angelo Tognon (4 months ago)
I want a giant otter as a pet
saamohod (4 months ago)
Just imagine Olivia converge on 500kg in 1 million years!
Sensei Tauntaun (4 months ago)
Hyaenas and hyaenadons (in the weasel family) got much bigger.
Ninja Man (4 months ago)
Do a thing about pangolins
Does this chick have Parkinson's?
stellvia hoenheim (4 months ago)
She kinda looked like a cow with that piercing
Poptartsicles (4 months ago)
@02:37 You missed a perfect opportunity for a pun. "Otterly terrifying." Hah!
blackreaper (4 months ago)
Hey...shut up your dumb face and annoying voice...
/encode (4 months ago)
Missed opportunity to say "otterly terrifying" lmfao
Ekaterina Alekseeva (4 months ago)
Oh my God! Olivia is sooooo much better in this video than she used to be, not to mention her improved looks. Her hair is stunning and just look at these earrings ). The intonation could be a bit more diverse but it’s just a matter of practice.
deathmeat (4 months ago)
Olivia you are a great host and beautiful person😍 , ignore the haters 😣😡✊
Jase Hurl (4 months ago)
She gets red
Stephen Robinson (4 months ago)
I thought it might be so the big lungs can store more oxygen
Joshua Tobler (4 months ago)
I want an episode on Giant Isopods. Are they really the same species as a wood louse? How the heck did they get that big? Also, are all those videos with people holding Giant Isopods hoaxes?
Steve W (4 months ago)
Great vid!
Mike Watn (4 months ago)
very pretty today
eli aguilar (4 months ago)
Liv is so cute! Love her look in this video
Mortimer Stroodle (4 months ago)
Otters also have other methods for heat conservation that might reduce the need for large body size. They have fur that traps bubbles of air for insulation. They constantly groom this fur to make sure its stays as efficient as possible at keeping them warm, and have special oil glands that help with grooming.
Supreme Reader (4 months ago)
“Sea otters are basically just really big weasels.”
hinrikelvar (4 months ago)
Good thing I wont be around to see those huge and otterly horrifying otters!
Jake Thornton (4 months ago)
i wonder if she knows about the otter future in south park lol
Pekezuz666 (4 months ago)
I think a lot of peoples opinion would change of her if she wore something a bit more revealing/attractive 😅
Owen Hunt (4 months ago)
Cuteness and terror are not mutually exclusive. Example: jungle cats, cute, also terrifying.
Gonzo Volante (4 months ago)
Its giant Allied Atheist Alliance!!!!!!
Brentavious (4 months ago)
God I would make sweet sweet love to our narrator today. Shes so adorable
Duke Frywokker (4 months ago)
So the fur of the otter has nothing to do with their ability to stay thinner, yet warm?
Heu Valadao (4 months ago)
Great. Now make a video about the only two biological genders, please.
ChicagoJon2016 (4 months ago)
Would you rather cuddle a polar bear sized sea otter or a otter sized polar bear?
Res Art (4 months ago)
Waith till polar bears become fully marine
CrocosNZ (4 months ago)
500Kg Sea Otters would be BOTH ridiculously cute AND utterly terrifying. Just like Polar Bears.
Blueeyesthewarrior (4 months ago)
Aww. All of these are animals adorable. I love it.
IraTheSquire (4 months ago)
"Much cooler" As cool as the ocean water? :P
Tahoe Jones (4 months ago)
mrscary3105 (4 months ago)
I am in the "Cute Camp" with giant otters. :)
drummer265 (4 months ago)
This is why I love SciShow. Saw the thumbnail and thought "probably because of buoyancy" only to watch the video and see there's more factors than I thought. Love learning more--keep it up guys!
Greg Christie (4 months ago)
Terrifyingly cute
Joseph Bloggs (4 months ago)
I just remembered why I stopped watching this channel. That voice is like nails on a chalkboard
shoutitallloud (4 months ago)
that ring...
TheWeeaboo (4 months ago)
That's what she said.
Abraham Drinkin (4 months ago)
The answer to this video is: we don't know, still researching.
rubadux (4 months ago)
0:15 The prewhaling idea! 😂😂
steveXracer (4 months ago)
The religion of evolution is a lie
Tim O'Brien (4 months ago)
Cute or terrifying? Both! "Aw, it's adorable... and it's going to kill me."
noybw333 (4 months ago)
Ooo love your earrings
Jak (4 months ago)
Colossal squid? Or is that fakery... It's hard to tell these days.
Alan Parris (4 months ago)
That upward inflection on the end of every statement she makes is super cringe.
qthoshi (4 months ago)
I knew seals were just water dogs!
Sous le Soleil (4 months ago)
God that white elitist accent is unbearable!
Perplexion Dangerman (4 months ago)
Bigger Propellers or Fins might be more efficient.  And big muscle for torque and horsepower.  sci show, not moto
Godzilla (4 months ago)
What about sperm whales?
348frank348 (4 months ago)
DJ (4 months ago)
can you not look straight and talk, can not follow you.
Michael Baker (4 months ago)
Unlike all those other marine mammal groups otters rely on fur for insulation. I believe fur is a better insulator than blubber and otter fur is ridiculously dense. That might be why they haven't got so big.
MsZeeZed (4 months ago)
Not being 500kg could be an advantage to the sea otter’s successful lifestyle (fur trade hunting aside). Unlike the other seagoing mammals they don’t have blubber, instead they have the outright densest mammalian fur which needs constant cleaning to trap an insulating air layer underwater. Extra energy expenditure & time for fur cleaning may preclude the extra hunting needed (25% of bodyweight per day) for a larger body size.
Alberto Portugal (4 months ago)
I am a baleen whale and I’m offended
Phoenix (4 months ago)
So many negative comments. I like Olivia a lot. She is......I dunno....Lovely.
Phoenix (4 months ago)
I was looking for Instagram account of Oilvia. Couldn't find. :(
SparrowFae (4 months ago)
Any weasel-y animal is cute. But is entirely possible to be TERRIFYINGLY CUTE.
Frost Hunter (4 months ago)
Idk... maybe tHaT’s WhAt ShE sAid...
Paul Sager (4 months ago)
You have the voice from #selfie who else noticed ?
Haiti LeBlanc (4 months ago)
Polar bear is the 5th example of mammal returning to the sea 🌊
Kayley199514 (4 months ago)
Could it be because otters have fur? Therefore they don't need the same kind of heat distribution
Dank Buds (4 months ago)
Would you care to explain to me how whales just developed bristles to catch their food I mean I'd like to get to work sooner can I just develop biological wings so that I can start flying
Kengur (4 months ago)
Its odd that you don't mention their food sources as the factor at all. Except the blue whales.
Kaela Olsen (4 months ago)
Kaela Olsen (4 months ago)
THANK YOU SCISHOW!!!!!! BUT WILL YOU PLEASE DO A VIDEO ON GLIOMAS!!?!?!!????? Or at least give me a yes or no???????
Blue River Bane (4 months ago)
Bad video. Giant otters will be incredibly adorable. Fake science.
Luigi Cappetta (4 months ago)
Very educational. Thank you.
trueperson22 (4 months ago)
3:04 scientific error. Ambulocetus natans is not the ancestor of whales. Please be more careful. http://evolutionfactormyth.blogspot.com/2013/03/ambulocetus-natans.html
trueperson22 (4 months ago)
0:39 scientific error. indohyus is not the ancestor of whales. Please be more careful. http://evolutionfactormyth.blogspot.com/2013/03/indohyus.html
Danielle M (4 months ago)
That would be .... OTTERLY terrifying. They missed a very good opportunity
Joy L (4 months ago)
Cool answers!
Ethan Ross (4 months ago)
I imagine sea otters aee limited by there much faster metabolism, compared to the slower metabolism of slow growing cetaceans and pinnepeds
Flaykz (4 months ago)
It sounds like you say: " The blue whale WAS the largest animal that's ever existed." Whats up with that?
Kaine Bishop (4 months ago)
+Flaykz Maybe you need to get tested for autism.
Flaykz (4 months ago)
Maybe you should check your privilege
Kaine Bishop (4 months ago)
+Flaykz Maybe you need to get tested.
Flaykz (4 months ago)
Frick you and you hearing privilege. Great that you could hear it correctly the first time.
Kaine Bishop (4 months ago)
+Flaykz Yes very clearly.
K Larsen (4 months ago)
Yamo go for "Otterly cute" - from a distance, that is...
bobbyjoejrfred (4 months ago)
I think sea otters are small because they followed a different evolutionary path. Whales, seals, and manatees have no fur and instead depend on their blubber to keep warm and have the cold water in contact with their skin. Otters on the other hand have some of the thickest fur of any mammal which traps a lot of air and keeps their skin from getting wet. Unless there is some process that puts pressure on them to lose that fur I don't think they'll grow a whole lot larger
James Neave (4 months ago)
Remember, whenever a god botherer tries to be clever with you and starts babbling about evolutionary "changes in type" or "macro evolution" just point out marine mammals like whales and seals. Proof positive that both of those [nonsense terms that they try to pass off as science] actually happened because nothing evolved air breathing lungs underwater!! 8D
Monkey Monk (4 months ago)
episode good, host, extra hot.
sfkeepay (4 months ago)
This science-based video starts by giving the finger to science. Stating an mere idea as though it were a fact is arrogant, dismissive, provocative, divisive, and above all, NOT scientific. This video says - with certainty - that the Blue Whale is the most massive animal ever to exist. But while that appears to be true, it's impossible to be certain. This may seem like no big deal, but this kind of sloppy communication is part of why public confidence in science, and expertise in general, has been eroding in the U.S. for decades. It's not a weakness to qualify your statements. If you take it on yourself to communicate science, THINK IT THROUGH. Blue Whales are thought to be the largest animals ever, but unless and until you can PROVE they are, STOP saying it like it's written in stone. People are smart enough to handle nuance, and they also remember all the occasions arrogant-sounding scientists made absolutist claims that turned out to be wrong. Stop being part of the problem!

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