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Re: T.Rex Feather Skepticism



On 9/14/05, Eric Martichuski <herewiss13@hotmail.com> wrote:
> >From: "T. Michael Keesey" <keesey@gmail.com>
> 
> >Sure, a full-grown _T. rex_ is very large; but they aren't that numerous.
> >Think of it this way: if you piled up the fur of all the grizzly bears in
> >North America in one pile and the fur of all the rabbits in North America
> >in another pile, which pile would be bigger?
> 
> The question isn't about grizzly bears vs. rabbits.  It's elephants vs.
> antelope.

That analogy doesn't fully work, either, since elephants are
herbivores, not carnivores. Well, a perfect analogy is impossible in
today's world, and I see your point. But....

> T. Rex was so large, it probably didn't need a whole lot of extra
> insulation thanks to its volume.

This is what spurred on my rant in the first place: everyone *says*
this, but nobody has *shown* it. As I said before, feathers are not
fur, and dinosaurs are not mammals: let's not make unwarranted
assumptions.

That said, without any further analysis, it does indeed seem *likely*
that adult giant tyrannosaurids might have *sparser* feathers, but
what gets my goat is people saying that they *probably did not* have
*any* feathers. And I would like to see more data about feathers vs.
fur as insulation.

I review hundreds of paleo-art images for The Dinosauricon.
_Tyrannosaurus rex_ is by far the most popular subject matter.
Feathered coelurosaurs were discovered in the '90s, tyrannosauroids
were placed back into _Coelurosauria_ in the '90s, a feathered
tyrannosauroid was published last year, and *still* most of the
submissions show the classic scaly monster. Sometimes they show the
classic scaly monster with a few true feathers appended, which is
really similarly unlikely.

>  A huge biped is probably somewhat
> different than a huge quadruped, thermally speaking, but not _that_
> different.

Yes, I don't see the number of legs to be of particular relevance here.

> And tiny (or decorative) feathers on a _biiiig_ rotting carcass are not in a
> good situation for preservation compared to an corpse with a higher
> feather-to-mass ratio.

My other point was that, in the formations which _T. rex_ is known
from, feathers are not preserved from *anything*: not from
deinonychosaurs, not from oviraptorosaurs, and not from birds. So far,
the fossils by themselves have nothing to say about whether _T. rex_
was feathered or not: the only things we have to go on are inferences,
e.g., phylogenetic bracketing, thermoregulatory models based on extant
animals, etc.

—Mike Keesey