Anonymous asked in Science & MathematicsZoology · 8 months ago

Why were animals in the past so much bigger than animals are today?

Animals like Godzilla and Tyrannosaurus were absolutely massive. Even mammoths, the ancestors of today's elephants, are much larger than any animals that exist today. Why were animals back then so much larger?

15 Answers

  • F
    Lv 6
    8 months ago

    Because they had lots to eat due to high levels of CO2 and a much warmer earth caused plants to grow very fast. This must have been due to the massive cars driven by the dinosaurs (though not T-Rex as their little arms would not reach the steering wheel).

  • 8 months ago

    The blue whale is the largest animal that has ever existed.

    Next question!!!!!

  • Anonymous
    8 months ago

    Godzilla was Japanese Sci Fiction.  Supersaurus was larger than TRex, which was then beat out by Argintinesaurus found in Argentina.  Do not forget the planet continents were placed more together in a supercontinent so as the continents moved to their present position today Argentina was  closer to the equator than it is now.  It just is that part of the world is not over run with people so the chances of finding a whole dinosaur is more likely compared to an area where they burned the land for agriculture and then plowed up the grounds to plant crops.  So bones looked like rocks and would have been cleared off the land...and a city built on top of it...or a highway or a whore house.   Much has happened before the rocks were identified as ancient bones.  So much is lost.  I believe there is Gigantasaurus as well.  Still waiting for someone to name it Bigbassturd-saurus

  • 8 months ago

    Godzilla is fictional.

  • What do you think of the answers? You can sign in to give your opinion on the answer.
  • Anonymous
    8 months ago

    Godzilla is a movie/story and (obviously) did not exist. Tyrannosaurus & the rest were 'created' by Freemasons to nail the evolution lie.


  • 8 months ago

    They weren't. For one thing, some dinosaurs were quite small; they get less press than the big ones. For another, the largest animal that ever lived is the blue or Sulphur-bottomed whale, still alive today. You are right about insects. They have a very inefficient respiratory system that limits their size. When the Earth's atmosphere contained more oxygen, they were able to get much larger than they do today.

  • 8 months ago

    o There is no Godzilla.  That's an actor in a suit.

    o The big mammoths were about the same size as big African elephants.

    o There were big dinosaurs, big mammals, and even big birds.

    o The biggest animals we have are the big baleen whales, with the biggest blue whales being bigger than any animals we find in the fossil record.

    Gigantism can occur in an arms race between predator and prey.  It can also occur if sexual selection tends toward "bigger."  There are conditions needed for gigantism.  One of them is a nice friendly environment that persists over millions of years.  The big dinosaurs had that.  So did the big terrestrial mammals and big birds for a while.

    The dinosaurs got trashed in a mass extinction event.  A big bolide impact can spoil your whole planet for years.

    More recently we've had a series of ice ages and inter-ice-ages.  These have thrashed big mammals.  Finally, the introduction of a super-predator doomed most of the rest of the big mammals, and the big birds.

    Humans.  We're the super predator.

  • 8 months ago

    The environment and atmosphere was a lot different back then and able to support the life then.

  • JimZ
    Lv 7
    8 months ago

    Growing large probably occurred in my opinion over a long time as predators got bigger and their prey grew large in a mutual evolutionary arms race to stay bigger since it added protection and ability to reach more and eat more food and to fight off predators. There are problems with growing large. The animal tends to slow down because the forces are so much greater for those larger animals.  

    Gigantism was not a bi-product of cold bloodedness.  That is rediculous and there is no example where that works today.  

    First there is no evidence that dinosaurs were cold blooded.  That is typically a claim from religious people, or dinosaur (meaning old fashioned and stuck in the mud) scientists.  Dinosaurs were warm blooded based on numerous lines of evidence from growth rate, vein density in bones and likely lung and heart capacity.  We have track ways that show they behaved and moved more like birds that cold blooded reptiles.  It seems that some people have an almost religious need to make dinosaurs primitive.  It is an assumption that isn't based on science and fact.  It is based more on their desire for it to be true.  

    For an animal to grow large, it needs to be stronger than a smaller animal and have more effective circulatory, respiratory, cooling, etc systems.   The idea that dinosaurs were slow reptiles that lived in swamps is hundreds of years old and it is junk science yet those ideas die hard.  

  • 8 months ago

    Godzilla is fictional

    most species of mammoth were only about as large as a modern Asian elephant 

    Dinosaurs were indeed larger...  see reference. In summary:

    Theory No. 1: Size Was Fueled by Vegetation

    Theory No. 2: Self-Defense

    Theory No. 3: Dinosaur Gigantism Was a Byproduct of Cold-Bloodedness

    Theory No. 4: Bony Head Ornaments Led to Larger Size

Still have questions? Get answers by asking now.