Dinosaurs Never Held Heads High

richard_za writes "The common notion that long necked dinosaurs held there necks high to graze from treetops has been proven impossible. Roger Seymour, from Adelaide University's Environmental Biology Department and Harvey Lillywhite from the University of Florida. According to a research paper published at the Proceedings of the Royal Society in London, he explained that due to heart size and metablic rates the only way they could have functioned on land was with a horizontal neck. This flies in the face of images popularised in Hollywood movies such as Jurassic Park. However it is doubted that this new evidence will have any effect on the Mozilla Project."

Comments

mozilla will be affected most of all

[VAXGeek]

actually, mozilla will be affected most of all. they do have the slowest metabolism rate out of any open source project i've ever seen.
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a funny comment: 1 karma
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Am I the only one...

[NecroPuppy]

...who thinks that a story about dinosaurs is somehow appropriate for election day?

Four chambered hearts

[Epeeist]

I went to a seminar in Manchester a couple of years ago where it was argued that long-necked dinosaurs must have four chambered hearts.

Apparently if they had two chambered hearts then when they bent down to drink the hydraulic pressure would have made their heads explode.

Reality and fiction

[iamsure]

Lets step back for a second before we bash Crichton. In Jurassic Park, he was one of the first authors of popular dinosaur fiction to display VERY controversial, and very relevant theories.

Like what?

Like the familial instincts, like the pack hunt, like the individualism of some species, etc.

Sure, the movie dumbed some of it down, but book was really very groundbraking, and the sequel was even better.

We have to understand that authors have to capture both the truth AND the common perception of things, and try their best to balance them.

oh really

[Anonymous Coward]

As somone with a biology background, if you studied the skeletal remains of a giraffe you might think the same thing. Due to the fact that I don't think there has ever been enough soft tissue find that could irrefutably say that these animals did not have valves for blood flow in their necks. I mean for goodness sakes they still are divided on if they were poikilothermic or homeothermic, if they were endotherms or exotherms...so given we know very little about their metabolism anything based on metabolism is a best guess at best :) Ok ok I did take 2 semesters of classes on dinosaurs.... Anyway just kinda found this one ridiculous.

Re:oh really

[Bilbo]

Seems that every few months we see yet another SHOCKING DISCOVERY about dinosaurs and how they lived. Everyone has his pet theory, and the more controversial, the better. The truth of the matter is, we don't have a clue!

Let's face it. We're looking at old, scattered fragments of bones. We can come up with some interesting theories, mostly by comparing ancient bone fragments to more modern species, but they are still people making long shots in the dark. Worse yet, factor in peoples' natural tendency to seek the limelight with some "ground breaking" new theory, and you see why we have these "new" theories cropping up all the time.

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Re:oh really

[Anonymous Coward]

Hi, here is another one, who teaches zoology at the undergraduate level.

You are right. This article and its arguments are crap.

The giraffes have a blood corpuscle (like a fine branched network) which helps to relieve the pressure above (i.e. closer to the head) that network. This way the giraffes' heads don't explode from the water column when it leans formard to drink water.

Of course they were homeothermic:

1: The fine canals inside bony tissues are of a kind only found in the warm-blooded mammals and birds, but not in other amniotes like crocodiles, lizards, snakes, or turtles.

2: Birds are dinosaurs, in the same manner as bats are mammals. The are thus strong reasons to believe their most proximate ancestors also were warm-blooded. [Somewhat circular]

3: Erect posture. You just cannot walk upright for long distances, lifting your own body weight, unless you have the metabolism for it.

4: Proportion between predators and prey. In current, homeothermic ecosystems (like the African Savannah) there are about 1-5% predators in terms of body mass. In ecosystems dominated by cold-blooded predators (crocodiles or large varans) there may be up to 30% predators. In Perm, before the dinosaurs, the predators were about 10-30% of all fossils. During Triassic, Jurassic, and the Cretaceous the predators sank to 1-5% of the fossils in terms of (estimated) live body mass; the same is true for mammalian dominated fossils more recent.

Cheers!

Erect and long!

Proven?

[AlphaHelix]

Nobody ever "proves" anything in any science. Particularly not when making speculative calculations about millenia old animals about whom we only have fossil information.
* mild mannered physics grad student by day *

Not "proven" or "impossible"

[Medievalist]

OK, first of all this is an old argument. No conclusive "proof" available at this time for either faction.

There are several possible anatomical features that would invalidate the math used: for example, the long-necked dinosaurs could have valvular tubing (either traditional valves like a giraffe, or structures similar to Tesla's valvular fuel piping) in their necks. There could also be muscular arrangements for peristaltic pumping and flow control - the peristaltic pumps in mammals are weak, but that doesn't prove anything about dinosaurs. I am not aware of any complete soft-tissue fossils of dinosaur necks that would prove or disprove the existence of such structures - post 'em if you got 'em.

Other arguments have been made as well - for example, if a brachiosaur can't lift his head for any length of time, he can't drop it for any great length of time - the blood would pool in his brain (rapidly, since the efficiency of his heart as a suction engine is likely much poorer than as a pressure generator). So, given that such a huge creature would require tremendous amounts of fluid intake, how did they drink without passing out? The fossils don't cluster around waterfalls as far as I know (again, post 'em if you got 'em).

Now, as computer geeks, we're all supposed to have some familiarity with LOGIC. So we should all know that it is nearly impossible to PROVE a negative - and astronomically more difficult to do so when the bulk of the evidence is obscured. Most paleontologists agree that the fossil record is necessarily incomplete due to the unusual circumstances required for fossilization and the tremendous variance of species diverisity over geological time periods.

--Charlie