Jurassic park

[JimmyDavid]

I know a bit about dinos and Jurassic park was one of my favorite movies ever ( the scene where the t-rex attacks them in the rain outside the fence, is the most dramatic scene ever shot, in my opinion).
But i was watching part 3 (again) and still don't understand where they got the idea that a Spinosaurus could ever kill a t-rex. It's absurd. I't like a battle between a croc monitor and a Komodo...
The fact that they made the spinosaurus steps sound heavier than the t-rex's is itself a wrong fact. Any average t-rex was larger and heavier than a Spino.
Spinos don't even run second, since Carcharodontosaurus and Giganotosaurus are also larger (even than a t-rex).
Spinos were just a long, slender and shy dinosaur that had mostly fish for a diet.

[Katt]

A spino (spinos were still quite a long therapod) being able to kill a T-rex, that bothers you more than say, dilophosaurs with frills and spitting posion? Not to mention, they're bigger in real life?

How about velociraptor which in reality is only a bit bigger than a chicken being man sized in the movie? Considering that Utahraptors are actually man sized? Then again, they were discovered after the books were written.

Oh and that fact the stegosaurs tail spikes were horizontal, not vertical, same with the dorsal plates.

So many things wrong with JP I, II and III, but the movies are still kick butt.

I love how the "velociraptors" have a hierarchy.

I took "dinos" in University, one of my favourite classes, a real eye opener, especially learning about T-Rex.

[JimmyDavid]

I think you mean Compsognatus was the size of a chicken. (?) But yeah, velociraptors were not too big either. Maybe 3-4 feet tall.

[concept3]

velociraptors were covered in feathers and were about the size of a sheep. So three feets is pretty close. I watched a program, they found the best preserved fossils of a raptor in China. I could not find any links on the net though/

[JimmyDavid]

Velociraptors had feathers? I never hear of that. are you sure?

[Katt]

Oops, yes, velociraptors are bigger than I remembered, but I wasn't thinking compy's.

I've heard the feathered dinosaur thing. In fact, I've seen the fossils of those chinese raptors.

T-Rex chicks are thought to have been covered in down.

I don't think the feathers dinos had are like the feathers birds have now.

[VI Reptiles]

Before they had scales they had feathers, they were more bird like. Just saw this on the discover channel


VI Reptiles

[JimmyDavid]

Are Dinossaurs part of reptilia? I think an animal must have a scale covered body to be in reptilia.
Then again, so they must be cold blooded and some scientists are starting to say that some dinos were not.

[JimmyDavid]

Nevermind. I think dinosauria is a group itself. It's just that i picture dinosaurs as reptiles.

[Removed_2815]

Originally posted by JimmyDavid
Then again, so they must be cold blooded and some scientists are starting to say that some dinos were not.

I've heard this too...
I believe the idea behind this is not so much that dinosaurs had some internal mechanism for maintaining homeostasis (constant temperature regardless of environment - like humans) but, rather that the sheer size of some of the animals would cause the body temperature to be slightly elevated compared to the outside environment. This heat production would come about through regular metabolic/physiological processes such as digestion, locomotion, etc. Since the surface area to volume ratio decreases as an object gets larger, these beasts would not be able to dissipate heat effectively (large volume compared to considerably small surface area in most cases, relatively speaking), hence a net build-up of heat.
I think to say that a dinosaur may have been warm-blooded is misleading, as most people think of endothermy when they hear that word.
I am by no means a palaeontologist but this is what I seem to recall from lectures.
Cheers,
Ryan

[KrokadilyanGuy3]

Yes, Dinosauria are a subsister of all modern living reptillia which makes pretty much makes them reptiles.

But then again, It's who's classification you wish to follow.
Zane

[Scales Zoo]

Originally posted by RMBolton
I've heard this too...
I believe the idea behind this is not so much that dinosaurs had some internal mechanism for maintaining homeostasis (constant temperature regardless of environment - like humans) but, rather that the sheer size of some of the animals would cause the body temperature to be slightly elevated compared to the outside environment. This heat production would come about through regular metabolic/physiological processes such as digestion, locomotion, etc. Since the surface area to volume ratio decreases as an object gets larger, these beasts would not be able to dissipate heat effectively (large volume compared to considerably small surface area in most cases, relatively speaking), hence a net build-up of heat.
I think to say that a dinosaur may have been warm-blooded is misleading, as most people think of endothermy when they hear that word.
I am by no means a palaeontologist but this is what I seem to recall from lectures.
Cheers,
Ryan

My gut feeling has always been exactly what you wrote.

Snake eggs give off heat, our large monitors and pythons are warmer than their environment. Metabolic processes create heat, proven science - and the larger the reptile, and surface area stuff is exactly what I've been thinking, and it makes sense!

Ryan

[Katt]

I'd like to ask, what exactly is a reptile?
Dinos weren't reptiles, they were quite different from the large reptiles that lived before them (like Dimetrodon).

Reptilia is an outdated and invalid classification.

[Cake]

Im on the same lines as RMBolton, but would like to add some more info to the warmblooded/coldbloobed debate

There is also inertial homeothermy to be conisdered when talking about large exothermic(cold blooded) animals. A large body size once warm takes a long time to cool down, its all surface area to volume ratios. Its the same priciple that allows the leatherback sea turtle to venture into the cold north atlantic in search jellyfish, returning to the gulf stream when their body temperature falls.

Inertial homeothermy would allow individuals to "warm up" during hot periods and then become active during cooler periods, expoiting niches that were not previosly availible.

Some large dinosaurs have also exhibited bone histology similar to endothermic animals in which they contain structures similar to haeversian(sp?) systems, which is a charecteristic of endothermic(warm blooded) animals.

The long neck length of the brontosaurus leads some reasearchers to think that it may have possesed a four chambered heart. Which is another endothermic charecteristic.

[JimmyDavid]

Katt, a reptile is a creature with scales, cold blood and a back bone.
I think dinosaurs had all that, i just don't understand what makes them different from modern reptiles, then.