*Zaccheus* on 16/10/2007 at 17:20
Quote Posted by SD
More like how the hell does something like that fit on Noah's Ark!
Unless they took hatchlings on board. :p
Quote:
One theory is that they didn't move- much. Their long neck would swing about giving them a huge grazing area without having to move at all. They would walk very slowly swinging their little, easily moveable head back and forth grazing.
Is that the same theory which says that their neck wasn't bendy but quite rigid because otherwise it couldn't have taken the strain ?
Chimpy Chompy on 16/10/2007 at 17:28
When I was a kid reading dinosaur books (circa late 80s) the rather crappily named Supersaurus and Ultrasaurus were the biggest ones found so far. But I take it they've been, er, out-supered?
Turtle on 16/10/2007 at 17:36
Quote Posted by Vivian
How the hell does something like that
moveRoller skates and subservient mammoths.
Vivian on 16/10/2007 at 17:47
Quote Posted by Chimpy Chompy
When I was a kid reading dinosaur books (circa late 80s) the rather crappily named Supersaurus and Ultrasaurus were the biggest ones found so far. But I take it they've been, er, out-supered?
Yup. Isolated bits and bobs of giant, often armoured sauropods called titanosaurs have been popping out of argentina and other places for a while now (Some goons used up all the hyperbolic names early on, so now they all get saddled with names like futalognkosaurus.) Based on some frankly dodgy scaling of smaller animals to fit their really fragmentary remains people have suggested silly things like 100 tonne body masses for (
http://en.wikipedia.org/wiki/Argentinosaurus) Argentinosaurus, but I really have trouble with that. 25 tonnes (four average-sized elephants) a leg standing still? What sort of leg is that?
Nonetheless, even if you take a more sensible view these were extremely big animals. An 80 foot length seems like it might be probable, but I'm betting once some serious work gets done on this new complete-ish one they'll find that it is built very differently to smaller sauropods.
Sinister_Evil on 16/10/2007 at 17:52
is it improbable for a 20+ ton animal to have evolved an efficient muscle mass in order to move itself? was it like 2 tons of muscle,bone,integral organs and 18 tons of fat?
the most supported newer (fast-moving warm blooder etc dinos) theory for the long necks is to balance the long tails needed for defense.
SD on 16/10/2007 at 18:02
Quote Posted by Vivian
25 tonnes (four average-sized elephants) a leg standing still? What sort of leg is that?
It sounds a bit like mine to be honest.
Nicker on 16/10/2007 at 19:44
"Strontosarus track-ways discovered in alluvial plains of TTLG delta..."
With regards getting a titanosaur on the Ark... they obviously didn't, which neatly explains their extinction. (How many times do we have to go over this? )
Vivian on 16/10/2007 at 19:47
Quote Posted by Sinister_Evil
is it improbable for a 20+ ton animal to have evolved an efficient muscle mass in order to move itself? was it like 2 tons of muscle,bone,integral organs and 18 tons of fat?
the most supported newer (fast-moving warm blooder etc dinos) theory for the long necks is to balance the long tails needed for defense.
Yes, it would have functioned somehow. But as muscle weight scales with its volume and muscle power with its cross-sectional area, when you start getting very heavy you have to have more and more of your weight actually in leg extensor muscles (never mind all the other leg muscles, let alone the rest of your body) just to provide the power to stand. So animals start having to straighten their legs, provide more support passively, as they get bigger. Elephants, at ~10 tonnes, are about as straight legged as you can get. To get bigger, an animal has to be doing something pretty novel with it's leg design to avoid have 16 of it's 20 tonnes just as leg extensor musculature. Of course, it exists so it did something to move. But
what it did to move, thats an interesting question.
PS - most supported? By who? How is that a more relevant idea than the tail existed to balance the massive neck? Besides, ankylosaurs don't have massive necks, and they undoutably defended themselves with a long tail.
Hewer on 16/10/2007 at 20:09
Quote Posted by *Zaccheus*
Is that the same theory which says that their neck wasn't bendy but quite rigid because otherwise it couldn't have taken the strain ?
Yeah, that's part of it all. You can really only physically put two or three of those massive vertebrae together to see how they can move against each other, so they have done computer models which estimate how the necks and tails could move all together. If I remember right, only a couple of known sauropods could lift their head very high. Even straight out, they're still quite high off the ground. Even if they could lift their heads up high- they would pass out doing that. A giraffe has a hard enough time getting blood up to it's brain, so a sauropod wouldn't have a chance. Their hearts were already the size of a beach ball, and it would take an even bigger heart to pump the blood that high- not to mention the pressure required.
Quote Posted by Vivian
Ah yes. (
http://links.jstor.org/sici?sici=0094-8373(199723)23%3A4%3C393%3ASSTDIT%3E2.0.CO%3B2-1) 'supersonic' sauropods. Well... maybe? What else can you say about a theory like that?
The neck thing. It's an idea, yes. Seems energetically inefficient to grow a massive neck instead of walking a few steps forward, but netherless they did evolve a massive neck and that is a reasonably good explanation ((
http://www.blackwell-synergy.com/doi/abs/10.1111/j.1469-7998.2006.00197.x) sexual selection, that old bugbear, is another idea, which I personally like even less). However the animal still has to move at some point, and with something like 6-7 tonnes of force going through each leg when it's
standing still it would have had to be VERY careful about how it moved. Obviously it worked, but I'd love to see how.
I think I remember reading in this forum a couple of years ago that someone was a real-life paleontologist- is that you? I'm definately a hobbiest- just really interested since I was a kid. And still to this day, if I got three wishes from a genie- #1 would be "I want to see dinosaurs!"
*Zaccheus* on 16/10/2007 at 20:33
Quote Posted by Hewer
A giraffe has a hard enough time getting blood up to it's brain, so a sauropod wouldn't have a chance. Their hearts were already the size of a beach ball, and it would take an even bigger heart to pump the blood that high- not to mention the pressure required.
Good point !
:cool:
