How Did Dinosaurs Get So Huge?

  • Publicado el 2 oct 2017
  • Part of why we’re so fascinated with extinct dinosaurs it’s just hard for us to believe that animals that huge actually existed. And yet, they existed! From the Jurassic to the Cretaceous Periods, creatures as tall as a five-story building were shaking the Earth.
    Produced in collaboration with PBS Digital Studios:
    Want to follow Eons elsewhere on the internet?
    Facebook -
    Twitter -
    Instagram -
  • Ciencia y tecnologíaCiencia y tecnología

Comentarios • 1 841

  • Bogwedgle
    Bogwedgle Hace 5 días

    Bigger is generally better in a stable environment, but as we saw 10000 years ago when the ice sheets retreated, large animals just suck at rapidly changing environments. They're relatively few in number and reproduce extremely slowly which makes adaptation almost impossible and means bad years where a lot of the population die take decades or centuries to fully recover from, and they require so much food that if that food source is interrupted, they can't cope, if you cut a herd of 500 deer by 80% you still have a genetically viable breeding population, if you cut a herd of 50 mammoths by 80% you just don't.

  • cyberpunkspike
    cyberpunkspike Hace 9 días

    The largeness appears to be an adaptation advantageous in the following particular conditions.
    1. Ample amount of foliage that could be easily eaten, assuming your head was literally above all other potential grazers.
    2. Predators of limited intellectual capabilities, thus no planned or organized actions could tip the scales against favoring your size.
    This would work great until predators grew, which then keep selecting for becoming larger prey. Thus becoming a cycle, stupid predators select for bigger prey, bigger prey selects for bigger stupid predators. Which does appear to be what occurred. Thus explaining why size was selected for in the Jurassic.(?)
    That is until predators acquired intellectual or social adaptations, then size would become a liability. More size needs much more food, and would still be taken down by smaller predators. This would favor selecting the smallest and smartest predators, the smarter the the predator the smaller they could become. Being a smaller predator becomes possible, if you were smart enough to avoid being a bigger predator's lunch, which I'm assuming you could do... because you are capable of an organized take down of giant prey. Thus explaining why size wasn't selected for in the Cretaceous.(?)

  • Gabriel Blas
    Gabriel Blas Hace 10 días

    This makes me wonder if there's actually an extinct ancient marine reptile that could be bigger than the Blue Whale? Fingers crossed!

  • Oak synia
    Oak synia Hace 15 días

    They eat, alot

  • snappy452
    snappy452 Hace 15 días

    I love this channel so much. Also, I would like to send a fruit basket to the parents of Hank and John Green as a thank you for having, um, relations, at least twice. You both did the world a great service.,

  • Stephen Tudor
    Stephen Tudor Hace 16 días +1

    This is cool and we get different narrators too. all perfect in how they tell the story 👍🏻

  • Nachuak
    Nachuak Hace 16 días

    Didn't mass amounts of extra oxygen that existed in the atmosphere back then contribute to their size?

  • Frank Dvorak
    Frank Dvorak Hace 17 días

    Humans have lived for such a short time compared to sauropods. Just because we came after them doesn't mean our body plan is better. Human race is likely to go extinct soon, the way we over reproduce and act like locust on this planet will be our end

  • JulieBishop
    JulieBishop Hace 17 días

    dinosaurs lived for millions of years that big. It seems that having a bigger brain to be smart enough to build the atomic bomb and think ourselves into depression is more of a disadvantage.

  • Dione Esteban
    Dione Esteban Hace 21 un día

    Probobly bezcuse the earth is warmer

  • Bethanie Petitpas
    Bethanie Petitpas Hace 22 días

    Did the sauropods have feathers?

  • Clyde Cessna
    Clyde Cessna Hace 22 días

    You implied that the size of the dinosaur was an evolutionary dead end. It was my understanding that these animals were destroyed because of an external event: the Chicxulub meteor. That was not the dinosaur's fault and so their size irrelevant to their extinction.

  • Dark Pariah
    Dark Pariah Hace 23 días

    You answered "how," but not "why."

  • Uncle Phil
    Uncle Phil Hace 24 días

    Why aint platypuses huge?

  • james corvett
    james corvett Hace 27 días

    more O2 on Earth and possibly less gravity. the rock that killed them could have changed Earth gravity. And from what you read on the internet humans too were bigger.

  • Edward Foehring
    Edward Foehring Hace 28 días

    More 02

  • MrFrontenginedragste
    MrFrontenginedragste Hace 28 días

    I've always wondered if the earth was smaller or had less gravity.

  • instalite14
    instalite14 Hace 28 días

    I always heard that the oxygen levels were so high during that time was why they got so large.

  • Christopher Neely
    Christopher Neely Hace 29 días

    Convergent Evolution: EYES.
    and The Tail Club club. All the different species that formed a club as a tail, with or without spikes.

  • kanishq ruhil
    kanishq ruhil Hace un mes

    Nobody beats the blue whale

  • M Lourson
    M Lourson Hace un mes

    I bet that they got so big, because they lived long and longer they lived, more offspring they had. Sharks, lizards and snakes grow all their lives.

  • squid din
    squid din Hace un mes

    0:38 we are bigger. cough cough blue whale and Paraceratherium. these mammals were truly dinosaur sized so technically we did come quite close to dinosaur sized.

  • Down Hill
    Down Hill Hace un mes

    along time ago, Earth, had greater oxygen quantity which was why everything was larger. Plants were larger thus herbivores = bigger which in turn carnivores = bigger as well. Even the insects were big compared to the ones of modern time. A professor from i forgot which university did an experiment where he grew fishes in a tank that had high oxygen content... after several generations the fishes' offspring grew to larger proportions. You can find it on youtube.

  • chestnut5602
    chestnut5602 Hace un mes

    How did they grow so large but have such small nostrils and mouths? Even with more oxygen they would not be able to breath without a substantial amount of air pressure to help with breathing.

  • CaramelLeek
    CaramelLeek Hace un mes

    For a second there I thought I was watching SciShow.

  • Ben VS Ben
    Ben VS Ben Hace un mes

    Airbag suspension? No wander they went extinct, the maintenance costs alone would be staggering for a lifeform that spent all of it's time off road.

  • Jae KiDd
    Jae KiDd Hace un mes +1

    imagine us being any where from 30-60 feet & 1 to maybe 50 tons that would be crazy we'd be like huge Giants I wonder if we'd still be as smart or even smarter cuz everyone in Hollywood makes it seem like really big people are naturally stupid?!?

  • Nolan Schaeffer Jr.
    Nolan Schaeffer Jr. Hace un mes


  • 1206 Avenger
    1206 Avenger Hace un mes

    I have a question. I seen reptiles freeze coz they cold blooded, they need to heat themselves up before. That is why most reptiles hunt at days, except in deserts. My question is how did Pterodactyl a 9 feet flying reptile pulled it off when you need a lotta energy to flap your wings to keep yourself airborne?

  • SpiderEye_Golum
    SpiderEye_Golum Hace un mes

    Please do a video on which dinosaur was the most dangerous or deadly

    • SpiderEye_Golum
      SpiderEye_Golum Hace un mes

      I play this game called ark so if u can mention a few Dino’s that are the most deadly that would be great thanks

  • Daniel Binder
    Daniel Binder Hace un mes

    Not to mention the poles were at west and east at the time .befor the last pole shift. It makes a big difference on gravity because our planet is a football shape.

  • Daniel Binder
    Daniel Binder Hace un mes

    Ok and yes there was more oxygen .less gravity.and humans were big to. 12 to 18 ft tall. There was an experiment done on a pirana. The scientist recreated earth atmosphere of 200k years ago. The baby pirana grew 3 times it normal size.

  • Peter M. Eggers
    Peter M. Eggers Hace un mes

    Since the dinosaurs ruled the earth over 100 times longer than humans have existed, I think it a bit smug to imply their size wasn't an asset. In fact, their descendants still exist as birds. I suspect that their size had more to do with high oxygen levels due to vigorous plant growth. I'm thinking that the asteroid that ended their reign, destroyed a dinosaur "Garden of Eden" allowing the dinosaurs' "cockroaches" (mammals) to evolve in the wasteland, culminating in human domination.

  • themutantlizard
    themutantlizard Hace un mes

    I would take pictures and film them

  • Sagan Worshipper
    Sagan Worshipper Hace un mes

    So basically we have no idea. Thanks!

  • David Draper
    David Draper Hace un mes

    Another reason for the size would be that it helps create a warmblooded state. Modern crocodiles become pseudo-warmblooded as they get larger which helps them be more active for longer periods of time.

  • Nerd With an Opinion
    Nerd With an Opinion Hace un mes

    does this mean we can have a titanosaur sized platapus

  • wade cooper
    wade cooper Hace un mes

    Damn! Stop calling birds dinosaurs. They are birds, they lived alongside dinosaurs and have beaks not teeth. Similar bone features do not qualify them as dinosaurs and terasaurs did not have feathers. This is theory manipulation to promote evolution over intelligent design. The Titanosaurs could not live in todays' gravity or thin air and low barometric pressure, their leg arteries would burst.

  • Cohors Praetoria
    Cohors Praetoria Hace un mes

    U haven't answered the most imoportant question: what kind of heart can allow those sizes?

  • Daniel Staal
    Daniel Staal Hace un mes

    I always wondered if part if it was because of the size disparity between eggs and the adults - what if they just kept growing? Even a moderate sized dinosaur has to grow quite a bit from a fairly small egg, so they've obviously got the gene setup to grow quite a bit - and with the size disparity, it makes sense for the adults to lay lots of eggs and see which reach a decent size. Even watching the eggs at some point would be kinda futile, as the parents wouldn't be able to deal with the threats to their eggs as the threats are too small.
    So the dinos were programmed to grow, and the larger they were the safer they were. There's no real reason for them to *stop* growing as they age, just to slow down.

  • T Ly
    T Ly Hace un mes

    But let’s not forget Dinosaurs have been on earth for approximately 66 million years and early form of human only 200,000. So it remains to be seen if we are the longer lasting species. Seeing what we are doing to the environment and each other I highly doubt we can exist longer then the dinosaurs have.

  • Kimani Powell
    Kimani Powell Hace un mes

    It's hard to rap your head around. I still cannot image what it would be like to see a dinosaur roaming around.

  • Sam Adams
    Sam Adams Hace un mes

    No humans around. They were allowed to grow and flourish.

  • Robert Henry
    Robert Henry Hace un mes

    Wasn't the higher oxygen levels 100 million years ago also a factor? Plus the limits were largely set by the ratio of the cubed function (size and weight) to the squared function (tensile support levels of legs).

  • The Daves I Know
    The Daves I Know Hace un mes

    Wasn't there more oxygen in the atmosphere before the asteroid impact? More oxygen content means you can grow more, while of course needing to eat more, but that was plenty too given that plants were huge also. AFAIK

  • arie prajoedi
    arie prajoedi Hace un mes

    Maybe the gravity of the earth was lower than today.

  • Toms Thomas
    Toms Thomas Hace un mes +1

    Could you make a video of what life on land was like just after the non avian dinos went extinct? I mean just a million or so years after the K-T boundary?

  • Shane Berry
    Shane Berry Hace un mes

    We have far bigger animal's alive today. We have animal's alive today that are bigger than anything that's ever lived since the beginning of time. Their size doesn't amaze me any more

    • Hunter Smith
      Hunter Smith Hace un mes

      Shane Berry Land animals don’t get as big anymore.

  • CryptionGlich
    CryptionGlich Hace un mes

    Maybe they need to be tall to reach the cookie jar???

  • Error: Unknown User
    Error: Unknown User Hace un mes

    Im imagining an evolutionary arms race between herbivores and plants the plants grow taller to avoid having their yummy bits eaten and the herbivores growing larger to get to those plants

  • MercurySunlight
    MercurySunlight Hace un mes

    Gravity was less at the time of dinos.

  • J Jackson
    J Jackson Hace un mes

    What about talking about constancy of environmental conditions as relates to dinosaur evolution? Perhaps when environmental conditions are more constant, you get bigger creatures?

  • Issolom Issolom
    Issolom Issolom Hace un mes

    I love you hanks

  • intruder313
    intruder313 Hace un mes

    Metric tonnes / Imperial tons. Don't cross the streams!

  • Vincent Rodrigo
    Vincent Rodrigo Hace un mes

    1:28 what you are in math XD get it? ok nobody -_-

  • MR. Sasquatch x
    MR. Sasquatch x Hace 2 meses

    Big question:How do we even know they existed?yeah we've found bones but have we actually found a dinosaur?

  • scott gurney
    scott gurney Hace 2 meses

    Bigger brains may also not be better...................................................

  • DougtheDonkey
    DougtheDonkey Hace 2 meses

    Can you explain how reptiles turned into the first mammals and how those became more diverse?

  • Orion6699
    Orion6699 Hace 2 meses +4

    The dinos are gone... but they were around one hell of a long time. Without that asteroid impact they still might be around.

    • pinakabudlayngapangalan ngamapaminsaranko
      pinakabudlayngapangalan ngamapaminsaranko Hace 6 días

      That asteroid impact wasn’t the only reason why dinosaurs went extinct. Either way they would still be gone but i don’t think we would still be around.

    • Jonas Gudeliūnas
      Jonas Gudeliūnas Hace 19 días

      In some sense, they're still around. Some animals that live today, shares DNA with them.

    • squid din
      squid din Hace un mes +2

      they would be around, and we wouldn't.

  • y11971alex
    y11971alex Hace 2 meses


  • Kasey Brewer
    Kasey Brewer Hace 2 meses

    They ate their vegetables, and grew up big and strong. 😂😂😂😂

  • Demise- Jose
    Demise- Jose Hace 2 meses

    The reason why dinosaurs are so huge is because they are large lizards, REPTILIANS and reptiles are more vonarable tk be bugger and larger on hot climate mild whethers because their cold blooded metabolism allows them to manifacture food and grow in a way that no one could thought of,millions of years ago the earths climates was 35°C approximately 95°F,and cuz of natural selection dinosaurs were born to be that way small cold blooded reptillians with the ability to grow and adapt to new hot climate since birth causing them to be dinosaurs,now its different because of charles darwin philosophy

    • August Landmesser
      August Landmesser Hace 2 meses +1

      Some of arctic/antarctic dinosaurs were huge also, but climate there wasn't warm at all.

  • Counter Kidnapping
    Counter Kidnapping Hace 2 meses

    They eat too much protein

  • avyeris
    avyeris Hace 2 meses

    It’s all about roids bro. Ask KaliMuscle too, that’s how he got big.

  • He was an asshole, but
    He was an asshole, but Hace 2 meses

    How did Mandingo get so big

    PR DEACON Hace 2 meses

    I just realized they can say whatever and I’ll believe it.

  • noisepuppet
    noisepuppet Hace 2 meses

    We're gonna need some solutions to the blood pressure, strength of materials, and neurotransmission speed problems before we can pretend to answer these questions plausibly. And as the presenter acknowledges, this would only tell us how such huge terrestrial creatures were physically possible. We'd still wonder what made them feasible then and not now. A higher atmospheric concentration of O2 might be part of the solution. Anyway, I hate to see true mysteries trivialized and am afraid that the confidence expressed in videos like this is false bravado, given the current state of knowledge. There's a lot of science left to do. In fact we've barely started.

  • David Dyer
    David Dyer Hace 2 meses +1

    I would have mentioned that the atmosphere had a higher percentage of oxygen during the dinoaur's time.

    • Highfield Hunting
      Highfield Hunting Hace 2 meses

      Then you would be a conspiracy theorist. if oxygen was higher, the air would be more flammable.

  • Lelouch Strife
    Lelouch Strife Hace 2 meses

    they drank a lot of milk lol

  • Kostas Mponis
    Kostas Mponis Hace 2 meses

    More oxygen in earth then help them grow

  • 1212 12
    1212 12 Hace 2 meses

    *But humans are getting taller time by time.*

  • Diana Snow
    Diana Snow Hace 2 meses

    So basically, oxygen?

  • belvedere261
    belvedere261 Hace 2 meses

    One theory is oxygen levels were much higher then leading to
    Bigger creatures

  • FlakeTillman
    FlakeTillman Hace 2 meses

    I’ve heard that the air sacs in the bones was an evolutionary development meant to deal with the thin air of the Triassic period. So perhaps as the air grew more dense and oxygen rich dinosaurs were able to develop much larger than animals today due to their inherent advantage in aerobic capacity.

  • Zacimus the master Shooter

    I love how massive these sauropods are😃😃😃👍🏻👍🏻😎😎!!! Dinosaurs definitely have the advantage in size

  • Consistently Random
    Consistently Random Hace 2 meses

    I'd say gravity was not as strong as it is today, which is why trees and other plants got so big. 'Scientists' will tell you otherwise because of a lack of evidence but its just common sense. The earth didn't always rotate at the same speed as it does today. Perhaps the faster rotation lessened the force of gravity. Or perhaps the amount of atmospheric oxygen was greater, allowing these giant animals to carry more oxygen in their blood.

    MUI DAIKON Hace 2 meses

    I preferrably thought that due to the immense forestational growth the amount of oxygen being so much caused greater genetic growth

  • aousaous65
    aousaous65 Hace 2 meses

    Cool video

  • Hamlan Hisani
    Hamlan Hisani Hace 2 meses

    200 tons ! Not 145

  • vinia 22
    vinia 22 Hace 2 meses

    You're 2 meters tall? Highly doubt it mate

  • Ryan Rodriguez
    Ryan Rodriguez Hace 2 meses

    Can you use Feet instead of Meters for us here in America? That would really help us understand your size references better!

  • Paul Schmick
    Paul Schmick Hace 2 meses

    Probably because there was a thick layer of water vapor around the planet...called by some the firmament. This filtered out deadly radiation and allowed for greater size and longevity.

  • Jek Lee
    Jek Lee Hace 2 meses

    Could it be the high % of pure oxygen on that time

  • jerolvilladolid
    jerolvilladolid Hace 2 meses

    Because humans were not around to spear them. Mammals were on the same path, see mastedon, wooly mammoth. But humans ate them as soon as they got big enough. The biggest creature that ever lived, the blue whale, is a mammal afterall.

    • Hunter Smith
      Hunter Smith Hace un mes

      jerolvilladolid The largest land mammal to ever lived lived far before humans ever evolved and still was small compared to the largest dinosaurs.

  • DarkWolf
    DarkWolf Hace 2 meses

    Back then there was Lot more O² I think thats why

  • spinogurl123
    spinogurl123 Hace 2 meses +2

    I thought there was more oxygen in the atmosphere that also allowed the Sauropods to grow so large? Either way, I enjoyed this video and the things brought up I never even thought of :)

  • Purploy
    Purploy Hace 2 meses


  • The Goddamn Batman
    The Goddamn Batman Hace 2 meses

    Considering Dinosaurs were around for almost 200 million years, I'd have to argue that 'Bigger is better'. Lets see if homo sapiens even come close to that.

  • Nagsaw
    Nagsaw Hace 2 meses

    being giant sounds like a great idea until you think about how much food you need to stay alive

  • Einherjar beserkergang
    Einherjar beserkergang Hace 2 meses

    We are so smart !! Pinnacle of intelligence right here folks

  • Humphihzly
    Humphihzly Hace 2 meses

    How big were plants of the time?

  • shivercanada
    shivercanada Hace 2 meses

    Asking WHY Dinosaurs were so large is pointless as we don't even know how life of any sort started in the first place. Scientific theories are severely lacking.....cells just gathered themselves together in a primordial soup, is nothing more than MAGIC. Until Time travel is possible and one can slip into a higher dimension, we're only guessing, and guessing is not evidence, nor is it science.

  • Irene Bethel
    Irene Bethel Hace 2 meses

    Fascinating information about dinosaurs and I’m glad they are
    no longer around. Irene Bethel GOL-106 Summer 2018

  • Patrick Thomsen Mantzouridis

    Bigger isn't better?? Hmm...
    Can you remind me for how many years dinos were roaming the Earth?

  • Alex Santos
    Alex Santos Hace 2 meses

    The fisrts insects would be a nice thing to know.

  • Marc Dezaire
    Marc Dezaire Hace 2 meses

    Teddy Signs:
    What is ''pair production''? I hope you are joking when you mention cosmic radiation. Can you give a mechanism that is working in the Earth's core that explains the growing mass and that does not belong in the realm of pseudo-science? Plate tectonics is generally accepted, but not a growing Earth, nor a smaller and growing gravitational force. The Altantic ocean is a good example of two plates getting wider and wider because of volcanism (subsurface convection streams). The Mid-Atlantic Ridge is younger than the parts on both sides that are moving from it. Oceanic plates are heavier, continental plates are lighter and remain recognizable for a far longer time. Plates grow bigger, get smaller or get destroyed all the time.

  • The Hell Am I
    The Hell Am I Hace 2 meses

    Maybe because they had no moon at the time.
    A moonless earth.

    • The Hell Am I
      The Hell Am I Hace un mes

      How do we know it was the Earth's satellite since the beginning? Creation is one thing but was it a moon since it's formation?

    • Hunter Smith
      Hunter Smith Hace un mes

      The Hell Am I The Moon is nearly as old of the Earth and made of the same material. All evidence points to the Earth having had the Moon for billions of years.

  • Baoqing Ye
    Baoqing Ye Hace 2 meses

    the air sacs also allowed dinosaurs to obtain oxygen from the air more efficiently than mammals
    (having sufficient oxygen was also why insects in the Carboniferous period grew so large, except that in their case it was due to higher oxygen content in the air rather than any special adaptation on the prehistoric insects' part)
    another advantage of more efficient oxygen intake is it allows the animal to carry out more strenuous activity
    and that's why birds (i.e. the dinosaurs which have survived to the present day) are stronger flyers than insects or bats

  • David C.
    David C. Hace 2 meses

    Here's my hypothesis: it is a genetic predisposition to always grow no matter the species, but there is a gene defect that puts a limit, just like there is a gene that tells your muscles to stop growing, (some animals like the blue cow doesn't have this gene that's why they are so muscular) so dinosaurs didn't have this gene or it activated later in life, that's why they hatched from small eggs but grew enormous.

  • Chris K
    Chris K Hace 2 meses

    If I remember correctly, insects grew significantly larger back then due to higher oxygen percentages in the air. Now that oxygen percentages are lower, insects are much smaller. Could available oxygen percentages have anything to do with the massive land animals back then?