Martin Karne on 12/9/2010 at 12:11
Feathers of a bird... scratch that, of a dino
Vivian on 12/9/2010 at 13:48
Quote Posted by Al_B
That page seems to suggest that even if Dilong had feathers it loses them as it grows larger. Larger in this context seems to suggest a size slightly less than waist-high to an average human. I can't see why T-Rex would have feathers as it is (apparently) much larger and their function would seem to be useless.
Display surfaces, basically. You're right, thermal insulation is not only unnecessary but actually dangerous in a multi-ton animal, but it seems plausible that some plumage on the neck, forearms and tail may have been maintained as adornments. Dinosaurs seem to be very visual animals (based on birds).
kabatta on 12/9/2010 at 15:18
That's very implausible. Flesh eating dinosaurs don't have feathers. Sure, we have flesh eating birds, but that's a poor analogy. Dinosaur studies are very flawed. FLAWED, I SAY! :mad:
Hewer on 13/9/2010 at 03:03
I've heard it's possible that T Rex chicks likely had down and stuff, but, yeah, a full grown Rex would only have some display feathers on like the head and tail.
Tocky on 13/9/2010 at 03:31
Indeed kabatta. It's just these kinds of things that happen when dinos being attacked by sharks and carrying a chicken under each arm become fossils. Plus I don't see anything so concave about concavenator. It looks pretty convex to me.
In all seriousness I'm a firm believer in form following function as in the sadddleback tortoise developing due to higher vegetation. I figure spinosaurus came about due to the difficulty of larger dinos to bite effectively from above. Could be ass thinking for all I know but the fragile ones could work as a breakaway distraction like a lizzard tail. It could even choke a large attacker while it got away. As long as it is logical I have no trouble swallowing it myself. A mating headdress of feathers seems farfetched in kill or be killed land.
I haven't the foggiest how feathers came about. Was blood originally channeled through them to act as cooling radiator fins? Did they cool each other like fans? I just can't see such a structure having only a display function originally. I could see them as defensive quills which found a further use in display but this was a harsh world where any form not working as a survival mechanism would be weeded out quickly. Even the fins of todays catfish serve the dual purpose of navigation and stabbing to get away from a predator. Grab one wrong and find out. Display accounts for some odd variation in a more gentle world as it is today. Not so as it was then. What say you?
Vivian on 13/9/2010 at 08:32
Quote Posted by Tocky
I figure spinosaurus came about due to the difficulty of larger dinos to bite effectively from above.
In prey animals like hadrosaurs etc that actually makes some kind of sense - a lot of bite marks are found on the dorsal aspect of the base of the tail, where the major locomotion muscles are located (the caudofemoral muscles), and so a large fin would make it more difficult to bite deep enough to have an effect on movement. In spinosaurus itself, and other sailbacked theropods like Acrocanthosaurus, its had to imagine predation being much of an issue. If they weren't apex predators in their respective ecologies its pretty scary to imagine what was.
Quote Posted by Tocky
A mating headdress of feathers seems farfetched in kill or be killed land... Display accounts for some odd variation in a more gentle world as it is today. Not so as it was then.
Right - so the Cretaceous was no more or less vicious than todays wild areas. Mating would be of equal or greater importance to killing stuff, its just that the 1001 shitty discovery channel dino shows only focus on the killing. The 'land of the dinosaurs' hyperbole that paints the mesozoic as some kind of ecological thunderdome is almost certainly bullshit. If you've been watching Clash of the Dinosaurs, its a prime example of that sort of rubbish, which is particularly unfortunate as I was a consultant on it - at least half the crew wanted to make a fully rounded doc on dinosaurs as actually functional biological creatures, so sexual behaviour, roosting, social interactions, birth, death, development etc, but they got overruled by the management who just wanted them depicted as literally running round screaming and killing the whole time because 'thats what sells'.
Quote Posted by Tocky
I haven't the foggiest how feathers came about. Was blood originally channeled through them to act as cooling radiator fins?...
The first feathers seem to have been fluffy things that lacked a central shaft, like the down of chicks. Seems likely these were just for thermoregulation, like mammal hair etc. The more 'feathery' feathers with a central shaft and interlocking barbs and barbules show up later, but the actual reason for them evolving is still unclear. The theory I subscribe to is that these more 'feathery' features evolved as waterproofing. The fine structures of the more complex feathers acts in a very similar way to materials like goretex - a fine, unwettable mesh that allows air through but captures water as small, surface-tension defined droplets that literally fall off the surface. Kinda makes sense - once you're covered in fluff, being waterlogged quickly becomes an issue. And if you developed feathers as insulation because you're endothermic, their function as a thermal barrier is going to be severely impaired if you let them get wet. The advantage of this theory is that it provides a fairly plausible function for the longer forearm 'wing' feathers - they may have been useful as a kind of umbrella to shelter hatchlings under when brooding (both male and female brooding are pretty common in birds, so that wouldn't necessarily limit wing-type feathers to females).
Shug on 13/9/2010 at 12:50
More like bi-curious, you stud Vivian
Tocky on 14/9/2010 at 03:10
Quote Posted by Vivian
In spinosaurus itself, and other sailbacked theropods like Acrocanthosaurus, its had to imagine predation being much of an issue. If they weren't apex predators in their respective ecologies its pretty scary to imagine what was.
There were taller though and for sailbacks to make it to big they had to pass the small stage. I have a spinosaurus tooth btw.
Quote Posted by Vivian
Right - so the Cretaceous was no more or less vicious than todays wild areas.
I don't know man, I think we got a do over on the level of clawy teethy things but I defer to your judgement naturally.(
http://s681.photobucket.com/albums/vv174/NGCalfee/?action=view¤t=087.jpg)
Inline Image:
http://i681.photobucket.com/albums/vv174/NGCalfee/th_087.jpgnicked on 14/9/2010 at 17:38
Yeah, but you're thinking from a human perspective. Yeah, a person running around the Cretaceous jungles would be lunch pretty quick, but when you scale all the wildlife up, there's gonna be little difference in behaviour between a big carnivorous dino and a lion, for example.
Vivian on 14/9/2010 at 18:23
eeeexactly. PS whoever did the jesus saddle tag I'm totally telling everyone about it, palaentologists will love that one.
