What, if anything were the feathers for? Obviously not flying. Were they for heat dissapation or something? I realize its probably not known for sure…just looking for what the theories are. I saw an article on Velociraptor now being added to the list of dinosaurs that had feathers and it made me curious why they might have had them.
-XT
Feathers are insulation. Think of an eiderdown jacket.
Feathers also provide UV protection to the skin under them.
Feathers pull out when bitten, and they cushion the blow.
Plus it’s possible that the chicks dug them.
I’m not claiming that it was the main driving force, but if it was acting, sexual selection would have been enough.
Is there now a consensus that dinosaurs had feathers? I know that shows on Animal Planet seem fond of showing them with excessive plumage, in bright colors, but they also go into great detail about their social and mating habits, which seem like nothing more than conjecture.
The Times speculates on the Feathered Velociraptor like so:
They worked their way through college as Vegas fan dancers.
What their original purpose was, we may never no. They may have been part of courtship displays, for conserving body heat, or any number of things. But they clearly weren’t for flight. It is thought that young T-Rexes had feathers, but lost them as they got older. Maybe that help them conserve body heat in a way that a larger animal might not need.
However, it seems unlikely that they were used for heat dissipation. What made you think that?
I’m suspicious of that report in Time. Here is what I think the researchers actually said about the discovery of feathers on that particular velociraptor, and I don’t see anything about being descended from ancestors that could fly.
You should keep in mind that these are conjectures - I’ve never seen any compelling evidence at all that dinosaurs had feathers. I think it’s an idiotic *assumption *based on minimal evidence and a lot of imagination, just like when my teacher told me Brontosauruses had a brain in their ass because otherwise it would take too long for a nervous system signal to go from the tail to the brain. Yeah she really said that. I read it in a couple of books, too.
What a crock of shit. An extra brain in their ass? Just like that? Did these people enjoy eating lead paint for breakfast or something? That would be the only animal EVER with two brains… and in its ass, of all places. Feathers on a lizard/dinosaur? Give me a break. You have a better chance of getting me to believe you had sex with 5 hot identical quintuplet blondes last night. Chances are better, anyhow.
On the other hand, if you tell me you had sex with both the Olsen twins at the same time… then I’d ask for pictures. But I digress. 
Use yer noggin, no one else is going to use it for you.
P.S. I’m not attacking your intelligence XT, I’m glad you had the good sense to *ask *why they *might *have had feathers, and you didn’t just take it as a given. You are smart. I’m just mad that people allow these ideas to propagate! Mad I say! 
Well, you know that birds have feathers, right?
And that birds evolved from dinosaurs, right?
So why would the idea that some dinosaurs had feathers be so shocking?
Archaeopteryx had feathers, and if Archaeopteryx isn’t a dinosaur, then the word dinosaur means nothing.
Of course, we have skin impressions of some dinosaurs and show scaly skin. It doesn’t seem likely that all or even most dinosaurs had feathers. But the little meat eaters that evolved into birds might very well have had feathers. It makes as much sense as reasoning that because dinosaurs were reptiles, and modern reptiles have scales, that dinosaurs must have had scales.
It’s actually indisputable that some non-avian dinosaurs had feathers. If you haven’t seen any compelling evidence, you just haven’t been keeping up with the literature.
One of the best known is Caudipteryx zoui. There are a number of other feathered dinosaurs known from the same site.
Since, cladisiticly speaking, birds belong to the lineage of theropod dinosaurs, it is also indisputable that some “dinosaurs” were feathered.
Large sauropods and some other dinosaurs had a very large sacral ganglion in their pelvic region to control their hindquarters and tail. This was actually larger than their brain. In the popular literature, this is sometimes distorted into saying that they had a second “brain” in their rump. While untrue, the idea does has a basis in fact.
Since the odds are actually 100% that some dinosaurs had feathers, documented very clearly in the fossil record, I could only wish that the odds were better that I had sex with 5 hot identical quintuplets last night. 
In my opinion, the most likely reason they first evolved was for insulation. Theropods most likely were homeotherms (“warm-blooded”). The smaller forms would have required some way to prevent heat loss even in tropical climates.
AFAIK there is no direct evidence for feathers in T. rex. However, since the tyrannosaurs were quite closely related to the small theropods that did have feathers, it is interesting to think that they may have had them. As you say, they may have only been necessary in younger individuals. Adults would have had a smaller ratio of surface area to mass, and thus retained heat better and not needed them.
There is no reason to imagine that they were used for heat dissipation. The outer parts of feathers have no blood supply and being made of a material that conducts heat poorly would have no capacity to dissipate body heat.
In fact, the feathered dinosaurs that have been found, including Velociraptor, long postdate Archeopteryx in the fossil record. This has lead some to postulate that these feathered non-flying forms are actually descended from ancestors that could fly, like Archeopteryx. (Interestingly, Archeopteryx seems to possess a raptorial claw like that of the dromeosaurs like Velociraptor.) I find this a quite interesting scenario, though far from demonstrated.
Whatever the case, it is very clear at this point that the line between flying feathered avian dinosaurs like Archeopteryx, non-flying avian dinosaurs like Mononykus and Shuvuuia, feathered non-avian non-flying dinosaurs like Beipiaosaurus, Caudipteryx, Dilong, Protarchaeopteryx, Sinornithosaurus, Sinosauropteryx, and Jinfengopteryx, and flying feathered non-avian dinosaurs like Microraptor is very obscure. It is highly disputed where exactly to draw the line between “avian” and “non-avian” lineages; which of these feathered and flying forms belonged to which lineage; and whether non-flying feathered forms might have descended from flying forms.
[QUOTE=Colibri]
In my opinion, the most likely reason they first evolved was for insulation. Theropods most likely were homeotherms (“warm-blooded”). The smaller forms would have required some way to prevent heat loss even in tropical climates.
AFAIK there is no direct evidence for feathers in T. rex. However, since the tyrannosaurs were quite closely related to the small theropods that did have feathers, it is interesting to think that they may have had them. As you say, they may have only been necessary in younger individuals. Adults would have had a smaller ratio of surface area to mass, and thus retained heat better and not needed them.
There is no reason to imagine that they were used for heat dissipation. The outer parts of feathers have no blood supply and being made of a material that conducts heat poorly would have no capacity to dissipate body heat.
In fact, the feathered dinosaurs that have been found, including Velociraptor, long postdate Archeopteryx in the fossil record. This has lead some to postulate that these feathered non-flying forms are actually descended from ancestors that could fly, like Archeopteryx. (Interestingly, Archeopteryx seems to possess a raptorial claw like that of the dromeosaurs like Velociraptor.) I find this a quite interesting scenario, though far from demonstrated.
Whatever the case, it is very clear at this point that the line between flying feathered avian dinosaurs like Archeopteryx, non-flying avian dinosaurs like Mononykus, feathered non-avian non-flying dinosaurs like Beipiaosaurus, Caudipteryx, Dilong, Protarchaeopteryx, Shuvuuia, Sinornithosaurus, Sinosauropteryx, and Jinfengopteryx, and flying feathered non-avian dinosaurs like Microraptor is very obscure. It is highly disputed where exactly to draw the line between “avian” and “non-avian” lineages; which of these feathered and flying forms belonged to which lineage; and whether non-flying feathered forms might have descended from flying forms.
As Colibri mentioned, it wasn’t Tyrannosaurus that was found with feathers, but a relative, Dilong paradoxus, a Chinese theropod. Dilong was, of course, a tyrannosaurid, and thus often referred to as a “tyrannosaur”, and you know how the popular press handles vagueries of taxonomy… However, Dilong also happens to be one of the earliest tyrannosaurids, thus the speculation that maybe at least juveniles of later tyrannosaurids, such as Tyrannosaurus itself, might have had them as well.
This is almost certainly referring to Gregory Paul’s theory, as expounded in, among other places, his book Dinosaurs of the Air: The Evolution and Loss of Flight in Dinosaurs and Birds (though I recall first seeing the theory discussed in the out-of-print book Predatory Dinosaurs of the World: A Complete Illustrated Guide). Bascially, his argument is that Archaeopteryx was an early dromaeosaurid, and other more derived forms, such as Velociraptor and Deinonychus were descended from Archaeopteryx, rather than perhaps the other way around. George Olshevsky also had posited that all dinosaurs were descended from early avians (which he often referred to as the “Birds Came First” hypothesis), though I believe he’s distanced himself from that hypothesis of late, and concerns himself more with delineating all the current known dinosaurs, and sorting out all the synonyms, invalid names, and so on.
At any rate, as mentioned, the most probable answers to “What, if anything were the feathers for?” are a) insulation and b) display.
The authors do mention this in the paper:
The recent paper on Mahakala (Mahakala omnogovae - Wikipedia), which shows that primitive members of all three paravian lineages (troodonts, dromaeosaurs, and birds) were tiny, birdy, Archaeopteryx-like things, and that large, un-birdlike forms evolved numerous times in later members, also sort of supports the idea that they had flying ancestors (not to mention that some dromaeosaurs actually could fly, or were close to it, despite not actually being birds. If things like Rahonavis and Microraptor really are closer to Velociraptor than to modern birds, it means either that the bigger raptors were secondarily flightless, or that flight evolved at least twice, independently, in otherwise very closely related forms).
Dusting, I reckon.
Besides insulation, there has been quite a bit of speculation that feathers were used to help the beasts direct and manipulatethemselves. Flapping , some theorize, may not have gotten them airborne, but it could help them turn. One paper speculated that wings with feathers developed not to help them fly UP, but to help hold them DOWN, giving them better traction for climbing up trees and the like.
I don’t know if it’s true, but it’s intriguing. And it would help answer that age-old crioticism about how wing developed when “hal;f a wing isn’t good for flying” – but it’s pretty useful for pushing you down onto the branch.