A Theory about "Giant" Animals?

I know, this was probably mentioned before a couple times but I couldn't find anything..

but all this talk about giant Prehistoric Animals that we're trying to find alive today, has anybody considered that they'd quite possibly be significantly smaller than they were back then due to there being Higher Oxygen levels that far back in time?

Is it possible that these cryptids we feel cannot exist because they'd be too big to go unnoticed, have 'shrunk down' in a sense over the extensive period of time it may have existed?

Any thoughts?

In my opinion there long gone

Sad to say but species die out and things change just as the human race will eventually. However things do evolve from things before it so its possible there are similar things to what there was all them years ago. You never know.

reply to post by Somebodyelse7

I agree, I wouldn't be surprised if many of these are long gone, but I also believe that some of the past animals may have evolved into smaller species that we know today.

Just a thought

Its very very possible i mean look at a cat spitting image of a small tiger, A dog so similar to a wolf, even people have an amazing likeness to gorilla's!

Besides that though it all has to start somewhere and i do believe its all still evolving just its such minute changes you don't even realize its happening till hundreds of years later.

[edit on 16-8-2009 by Somebodyelse7]

www.abovetopsecret.com...

In terms of insects, it's very likely. Check out that thread. It's a bit scientific but I found some cool studies about insects and high oxygen environments that supports your hypothesis.

reply to post by ravenshadow13

Thanks for the link Raven, that's actually why I came up with this. I know that prehistoric insects were supposedly larger because of higher oxygen levels, and it makes me wonder if maybe it's something similar for other species?

Whether they're 'shrinking' or just evolved into newer but related species, I find it odd how unoften it's taken into consideration since it seems very likely to me.

I should note that by Giant animals, I'm referring to prehistoric animals similar to that which we have today, just much larger. Maybe they are infact still here, they just directly evolved into the smaller 'relatives' we have today?

I don't know, just an interesting concept that's been on my mind for some time now

reply to post by Akherousia


Yeah, no problem. I got what you meant... Um.

I wouldn't bet money on my answer but here goes:

I think that "animals" is a fairly loose term. I also know for a fact that animals evolve over time, and the chances of say a... tiger... existing ages ago in a much larger size and only evolving to modern day size is unlikely. Other mutations would have occurred, it would no longer be a tiger. Plus lack of fossil evidence.

But we do know that insects used to be larger. And fish. And reptiles. And birds. And some mammals (ground sloths, etc).

So my answer would be yes, there were giant animals which may have been SIMILAR to modern day animals. Ex. Megs and modern sharks.

But no they would not just be blown up versions of the same animals we have today. In order for the size to decrease, mutations would have occurred, and there would have been other mutations along with that.

How does that sound? (I could be completely wrong)

AS you already mentioned our planet has less oxygen then it did 65 million years ago. Its highly unlikely anything that is a lot bigger than an elephant is likely to survive at todays oxygen levels.
and yes as the oxygen started to get less and less animals and plants evolved, getting smaller to account for the missing oxygen

[edit on 19-8-2009 by loner007]

reply to post by ravenshadow13

Well then the question is how big would these changes be from the evolution?

Because I agree with your approach entirely, but the reason I bring this up is because I was having a discussion about the ancient giant Monitor Lizard of Australia called Megalania, and the other person brought up that there have still been sightings of Megalania reported, but as usual nothing has been confirmed. But I was skeptical about the concept of it still existing in it's present form and brought up the possibility that it may have evolved into one of the smaller species of Monitor's (or Goanna's, since we're talking Australia here) to adapt to the new environments that were pushed on it?

He shot it down in an instant and claimed that proportions of the skulls of recent Australian Goanna's are different from the skulls of Megalania. But would this even prove anything? I mean, if evolution is in question and the animal is living among us, just under a small guise, it wouldn't be just a case of shrinking down, would it? That just sounds illogical. So wouldn't there be a possibility that the bone structure and proportions of the skull would be different in a current species from an animal it possibly evolved from?

Like you said, it doesn't make sense for an animal to just 'shrink down' without other further changes..
If you look at ancient insects, even they were known to have slight differences from today's insects.

Though I guess the problem is it would be impossible to prove that one animal is an evolved form of one of it's larger species..

Any thoughts?
Am I going about this all wrong or am I possibly onto something here?

[edit on 19-8-2009 by Akherousia]