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Why No Giant Mammals?

Оценок: 28350 | Просмотров: 1789460
Hank gives a quick run-down of the reasons scientists think the land mammals of today are nowhere near the size of the largest sauropods. Some of them might surprise you! If you liked this video, check out more videos about natural history and paleontology on SciShow's sister channel, Eons: https://www.youtube.com/eons Like SciShow? Want to help support us, and also get things to put on your walls, cover your torso and hold your liquids? Check out our awesome products over at DFTBA Records: http://dftba.com/artist/52/SciShow -- Looking for SciShow elsewhere on the internet? Facebook: http://www.facebook.com/scishow Twitter: http://www.twitter.com/scishow Tumblr: http://scishow.tumblr.com SOURCES http://news.discovery.com/animals/how-dinosaurs-got-so-big-120131.html http://dinosaurs.about.com/od/dinosaurevolution/a/bigdinos.htm http://www.newscientist.com/article/dn19771-why-mammals-grew-big--and-then-stopped.html http://www.scientificamerican.com/article.cfm?id=land-size-limits-body-size http://ngm.nationalgeographic.com/ngm/0507/resources_who.html http://earthsky.org/earth/felisa-smith-why-mammals-havent-out-sized-biggest-dinosaurs http://www.sciencemag.org/content/330/6008/1216.abstract http://www.cam.ac.uk/research/features/mammals-vs-dinosaurs http://blogs.smithsonianmag.com/dinosaur/2012/06/when-mammals-ate-dinosaurs/ http://svpow.com/2013/02/19/personal-milestones-publishing-the-ph-d http://www.slate.com/articles/news_and_politics/explainer/2009/02/a_snake_the_size_of_a_plane.html http://www.dinodatabase.com/dinorcds.asp http://voices.yahoo.com/indricotherium-largest-land-mammal-ever-237482.html http://science.kqed.org/quest/2010/03/17/the-largest-land-mammal-that-ever-lived/ http://phenomena.nationalgeographic.com/2013/02/25/dinosaur-reproduction-not-ancient-gravity-made-sauropods-super-sized/ http://www.popsci.com/science/article/2012-02/hot-weather-makes-mammals-smaller-%E2%80%94%C2%A0what-does-mean-global-warming http://scienceline.ucsb.edu/getkey.php?key=427 http://www.smithsonianmag.com/science-nature/dinosaurs/How-to-Build-a-Giant-Dinosaur.html http://www.plosone.org/article/info:doi/10.1371/journal.pone.0028442 http://www.nmfs.noaa.gov/pr/species/mammals/cetaceans/bluewhale.htm
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Текстовые комментарии (3713)
dynomax101 (4 часа назад)
Information out of date, even for 2013. This video needs to be done over.
Nobushi Kensei (5 дней назад)
Cause evolution sucks...
Randy Lee (5 дней назад)
Lol just wait, rise in co2 nowadays relates to the beginning of life in history.
ATMOSK1234 (8 дней назад)
Why would a bigger mammal have a higher body temp then a small one? If anything I'd think it would be lower since it has more mass to heat.
Opal Dust (9 дней назад)
Reeee look how cute he looks with his braces
Andulvar (11 дней назад)
So what I got from this is that this channel doesn't do research.
T.A.C (11 дней назад)
Well I don’t think sauropods were exactly cold blooded, personally I think all Dino’s were warm blooded. I just think the sauropods produced less heat as they got bigger, gradually re-evolving a slower metabolism, and lower natural body heat.
Thom (15 дней назад)
Saying "Erbivores" instead of "Herivores." Come on. I realise you might want to use the French pronunciation when talking about cooking, but other than that, these dinosaurs were not eating rosemary and thyme.
LitGeekSquad Official (22 дня назад)
Because humans like big trophies
hunter hornet (23 дня назад)
I thought the idea of superheavy dinosaurs had faded away. Some even suggesting that they may not have even weighed a third of the previous estimates.
Freddy Pedraza (25 дней назад)
The big rhino lost his throne
Jack Doyle (1 месяц назад)
Isn't the most limiting factor humans? all the megafauna in the Americas and Australia was hunted to extinction when humans arrived.
seriously? really? (1 месяц назад)
So there are no large land MAMMALS but why arent there giant land REPTILES in the equatorial regions of the planet where vegetation is plentiful and so is the heat? We know the catastrophe that caused the mass extinction of just about all land creatures 64 m yrs ago. but the survivors were mostly of the reptilian sort, crocks, komodos stuff like that so why didnt they re-evolve to giants?
Noob Saibot (1 месяц назад)
Its not carbon in the atmosphere, but oxygen saturation and pressure. There have been numerous experiments on plants (increased co2) and animals (o2 mainly with fish) to demonstrate this.
Nykko Smith (1 месяц назад)
Dinosaurs aren't real
8Bit.Jay (1 месяц назад)
This is alot more bareable if you watch it at 0.75 speed. Chill out Hank, what's the rush?
Prehistoric Creature (2 месяца назад)
Indricotherium is literally the size of a Sauropod. And Palaeoxolodon Namadicus is even Larger.
Malligrub 1 (2 месяца назад)
Wrong, relatively recently extinct straight tusked elephant was 6 metres tall and weighed over 22 tonnes
Sarah Leonard (2 месяца назад)
I'm a little confused. Most of the reasons stated in this video would also have applied to the giant mammals of the past, who DIDN'T cook themselves, or crush themselves under their own weight, or die out immediately due to low birth rates. So the reasons are rather severely flawed. The only one that appears to hold up is the reduction in food supply.
paco ramon (2 месяца назад)
Wait how the blue whale is the largest animal with 25 metres if there is a 60 metres dinosaur
A FUCKING WHITE MALE (2 месяца назад)
This video is very racist.
dondodda don (2 месяца назад)
Humans kill everything... Justsayn lol
Sama Lass (2 месяца назад)
Here's a giant mammal https://i.ytimg.com/vi/aFKMZcr7ai4/hqdefault.jpg
Rigo Martinez (3 месяца назад)
Very likely there was a denser atmosphere back in those days
Rigo Martinez (3 месяца назад)
Yet intelligent design is out of the question. More whole in the theories of evolution than there is in Swiss cheese 🧀
Rigo Martinez (3 месяца назад)
I thought carbon was a product of human pollution
Air Conditioner (3 месяца назад)
If you think about it dinosaurs also had like 10 times the amount of time living to develop that big while mammals have only been around for like 60 million years ( as the dominant species)
Zeta Reticuli (3 месяца назад)
I recommend this video to people who still think humans grew to 60 meters tall and lived for 900 years.
Władca Wymiaru (3 месяца назад)
There is something that fit! Oxygen level! And warmth! Cretaceous period have up to 4000ppm of CO2 and 30% of oxygen! It was also longer and warmer than next period, by 4 °C than modern temperature! https://en.wikipedia.org/wiki/Cretaceous
viikmaqic (3 месяца назад)
smörgåsbord :D
Anthony Fremont of negativism (3 месяца назад)
Giant Sloths first died out 10,000 years ago.
Jasper Force (3 месяца назад)
But there were giant Wombats (the size roughly of At-At) in Australia fairly recently geologically speaking (within the last 100,000 years) and Australia has one of the warmest environments in the modern world... :s
Suhuyini Imoro (3 месяца назад)
i clicked on the vid just to comment BLUE WHALE then this guy ruins it .I guess it was a trap for people like me
TheLakabanzaichrg (3 месяца назад)
Today the largest mammals are the feminists.
Hans Hubner (3 месяца назад)
Global warming was good for the dinosaurs.
Prehistoric Matt (3 месяца назад)
And you think dinosaurs just laid eggs and walked away? Is your perception of caring parents stuck in the stone age?
Diana Snow (4 месяца назад)
Giraffes and elephants are pretty big
Kim Clayton (4 месяца назад)
I wished they still existed today.....providing they were vegetarians.  (gulp)!
Joshua davis (4 месяца назад)
I was waiting for him to say humans
Jagobot1 (4 месяца назад)
Does that mean that there is a possibility of these giant animals coming back if the environment allowed it???
PoopOnuGrave cameron (5 месяцев назад)
What about roseane and oprah
PoopOnuGrave cameron (5 месяцев назад)
What about rose and and oprah
tuffsmurfen96 (5 месяцев назад)
The blue whale is a mammal! A better title would be "why no giant land animals", I think.
ApaProductions (5 месяцев назад)
This is what you get when you have a non funny nerd reading jokes from a script
Who'sJames (5 месяцев назад)
Before even seeing it I said “Because they we’re too big to survive the Dinosaur’s Asteriod”
maximilianovvv (5 месяцев назад)
ACKSHUALLY Amphicoelias fragillimus is of doubtful existance since "it's bones were lost" and only drawings remain...simply put there's no proof that it's the largest -and before you try to prove me wrong just google the history of why that is the case. So the confirmed largest species are the patagotitans.
polished x gamer gta 5 (5 месяцев назад)
paleoloxodon is 24 tons and 17.1 feet tall at the shoulder making it the biggest land mammal
polished x gamer gta 5 (5 месяцев назад)
blue whale is a mammal
brittany crawford (5 месяцев назад)
Cause of humans
DGA2000 (5 месяцев назад)
You're not making people smarter. More knowledgeable maybe
The Religion Defender (5 месяцев назад)
Why u no like espicy foods?
Sniper_Kid_308 (5 месяцев назад)
Well there are... Elephants
Holly Wood (5 месяцев назад)
Whales are mammals
test (5 месяцев назад)
younger dryas comet impact also wiped out the huge animals from the last ice age. like the dinosaur extinction, but for massive mammals.
UnicornyBANG (5 месяцев назад)
I don't know that thing?!?!?!?!
Rursus (5 месяцев назад)
No pauses between sentences => unlike.
Yeoj Henrie Sayadi (6 месяцев назад)
Hi
kala captain (6 месяцев назад)
>Why No Giant Mammals? because we killed them all
vegeta black (6 месяцев назад)
Nope paraceratherium (BM-17t and height-4.8 max) is not the largest land mammal..it is the palaeloxodon namadicus (BM- 22T and height-5m max) which is the largest land mammal ever recorded
Il Papa Vitielo (6 месяцев назад)
The Platypus gives birth to eggs, so a giant platypus could work!
Dany Varna (6 месяцев назад)
He looks as a liberal beta cuckold :-/
J Mondragon (6 месяцев назад)
Also, humans. Most of that mammal megafauna they mentioned went extinct at almost the same time as human settlements started in the region. We are making nature evolve smaller, for it to survive us.
hunter hornet (6 месяцев назад)
i thought this might be interesting until i noticed who is the presenter. i cant stand his annoying voice. at least i dont have him subscribed.
Broockle (6 месяцев назад)
Dinosaurs cold blooded....? The small ones could be similar to modern reptiles but the really big ones probably had some amount of body heat I would imagine..... And Big Mammels could like Elephants adapt and produce less heat... why is body heat such a problem?
Lou Perez (6 месяцев назад)
he's cute
Adro Harv (6 месяцев назад)
we're supposed to believe that animals as much as 120 tonnes existed on this earth. Really
Peter Smythe (6 месяцев назад)
Dinosaurs were definitely warm-blooded, as were crocodiles. Look at the physiology of modern crocs and birds and the fact that birds are warm-blooded? And of course that other archosaur, pterosaurs, which were fuzzy, flying animals that could not possibly have functioned on reptilian-level metabolisms.
Suceava Gamer Boy (6 месяцев назад)
The blue whale is a mammal
Mr Pro Gamer786 (6 месяцев назад)
Wow a paractheruim actually lived on walked this planet a few years ago
Harsh Srivastava (6 месяцев назад)
But what about marsupial mammals? They give birth to poorly developed ones.
Alex Soetekouw Productions (6 месяцев назад)
But there are, right? Whales?
Athina Mohammed (3 месяца назад)
ShadowTron specimens of ichtyosaurs rival the blue whale in size
Władca Wymiaru (3 месяца назад)
They are comparable. Like blue whales ~120 tons average. 190 was really FAT one...like fat elephant 12 tons...not count.
ShadowTron (3 месяца назад)
Blue whales are over twice the weight of the very largest sauropods.... sauropods have nothing on whales
Władca Wymiaru (3 месяца назад)
Some Sauropoda reaches whales weight :\
ShadowTron (3 месяца назад)
No that's completely false. They're the biggest because the water helps to prevent them from collapsing under their own weight.
SilverJay (6 месяцев назад)
Explain paracertherium from your thumbnail then they were bigger than elephants at 4.8 meters at shoulder and 7.4 meters long and weighed 15 to 20 tons
San dro (6 месяцев назад)
This is pretty much same video as you got on PBS Econs "How Did Dinosaurs Get So Huge?"
Robert Szymanski (6 месяцев назад)
I say the reason why there's no giant insects is due to the oxygen level going down...down... really! You got the internet here...look it up! If I went in a time machine and bring a giant dragon fly back...it wouldn't survived our low oxygen levels.....
copyRtest1 (6 месяцев назад)
1:45 So one effect of C02 and Global Warming is that there will be more plantlife and in turn larger animals
TheIvangallo (6 месяцев назад)
Don’t really care about this but it was in my recommended so...
Tom Holland (7 месяцев назад)
More oxygen in the air. Spiracles limiting giant insects according to the oxygen content in the air.
Ascaithe (7 месяцев назад)
You may as well ask 'why aren't any land animals alive today as large as the biggest in the past?'
Phoenix Negative (7 месяцев назад)
Giraffe
Jared McCain (7 месяцев назад)
Dinosaurs never died out 65 million years and they still exist today
Abiy BattleSpell (7 месяцев назад)
so ima guess whales are warm blooded and ok cause the water cools em?
Glasses&Tea (7 месяцев назад)
Wow i forgot how long sci-show has been around watching this video almost 5years after it came out.
Amy Patchi (7 месяцев назад)
Whose watching in 2018?
Israel Diaz (7 месяцев назад)
well, dinosaurs just were giant wingless birds with feathers and warm blood.
Giannis Kalantzis (7 месяцев назад)
The only issue I have is that Amphicoelis fragillimus was only speculated to be that big from a single fossil. However, a better example to say was the largest dinosaur would be an argentinasaurus, patagotitan or even bruhathkayakosaurus. Which grew to an estimated 37m long, not nearly as long as Amphicoelis. This is why many palaeontologist doubt the legitimacy of the fossil, as all we have that remains are sketches from it and sizes as given by the palaeontologist at the site.
Sailor Barsoom (7 месяцев назад)
That's great, but what was NOT answered was: how do blue whales manage to be so big? I can get behind "they don't need the light bones because they're in the water" but what about long pregnancy and cooking themselves?
Hmmm Hmmm (7 месяцев назад)
*PARACERATHERIUM*
WorldCitizen83 (7 месяцев назад)
Because most mammals adapted to their habitat, that was getting smaller and smaller, because of the stupidest mammal of them all; ........? 50 points for the right answer.
10,000 Sub challenge with no videos !! (7 месяцев назад)
maybe we go smaller by the time almost all of middle schools have short and average...kinda short people MAYBE WE GET SHORTER BY TIME
Mull M (7 месяцев назад)
I always thought higher levels of oxygen in the time of the dinosaurs played a factor in their large size.
William Martínez (7 месяцев назад)
Well the blue whales are massive
pokenei (7 месяцев назад)
All speculations. Thumbs down.
Paul Mathew (7 месяцев назад)
Yo mama so big....She is scishow topic....
Luke Schroeder (7 месяцев назад)
Elephants?
Rum Mug the Orc (7 месяцев назад)
Damn metric system!!!!!! 🤬 still a great video anyway!!!!
The Jurassic Warewolf (7 месяцев назад)
customy units please
Hammerhead Monkey (7 месяцев назад)
I'm happy with my size. Thank you.
whiteknightcat (8 месяцев назад)
Why are there no megafauna? Because Noah couldn't get them on the Ark while the dinosaurs were stored as eggs. Ahahahahaha! (Now waiting for the Ken Ham wannabes to jump on this.)
Wasteland Wonderer (8 месяцев назад)
But what about your momma?
Neil Coss (8 месяцев назад)
What about whales (dozens of breeds) elephants (at least two breeds) bears, rhinoceros, hippopotamus, condors, etc. They're all pretty friggin' big.

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