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Re: re:Dinosaur Hunting techniques



>     >Actually, cheetah tails are held about as rigid as they can be,
>     >except at the base.  Cheetah's and other big cats use their tails as 
>     >dynamic  stabilizers, to turn on a dime at high speed.  This is 
>     >exactly the condition we find in the Dromaeosauridae.
>     
>     Don't cheetahs tails remain curved during a run during a turn?
>     And not straight out behind them but up over the back during a 
>     straight-out run?  

Because cheetah (and other cat tails) do not have the complex structures in
the tails of dromaeosaurids etc., they do curve and bend while they move.
If you watch slow speed films and stills of big cats hunting, you'll see
them holding them out and up behind them, probably the way dromaeosaurids
did as well.

>        However, though the tail is stiff, it curves in a variety of ways
>     that I don't see the reinforced tail of therapods doing.  Just how 
>     flexible do the tendons allow the tail to be?  Are we talking full 
>     rotation of the tail at the point it joins up to the hip?  I see that 
>     in deerhounds (I've been smacked in the face by tails often enough to 
>     know just how flexible they can be)

The tails of dromaeosaurids were incredibly stiff (one of the MAJOR
anatomical flaws of Jurassic Park was the raptor tails; another was the
raptor hands).  In dromaeosaurids and birds, the motion would all be in the
five-to-nine most proximal caudals. In other tetanurines, the tail was
more flexible, especially out to caudals 12-15 (coelurosaurs) or 20
(allosauroids and others).  In ceratosaurs, the tails were very flexible.

>       I've seen a young adult male cheetah at the Marine World in Vallejo, 
>     Cal.  I spent some time studyung it's feet, and was amazed at just how 
>     much it resembled my mom's dogs in build.  Cheetahs have such tiny 
>     heads to be compared to T rex. Not having seen all the T rex 
>     individuals you have, I bow to your expertise on T rex gracility, but 
>     cheetahs seem to be just the wrong animal to compare T rex to.  A 
>     Bengal tiger, perhaps, but not a tiny-jawed, spine-bouncing, 
>     stubby-clawed cheetah.

Actually, although T. rex was gracile (for a big animal), my first choice
for an analog is not the cheetah (that was forced upon me).  Instead, my
prefs for a tyrannosaurid vicar would be the Cape hunting dog, a predatory
hyanea, a wolf, or a phorusrhacid.
>
>     (the wrong legs on the T rex at AMNH?  I never knew that, thanks!)

You're welcome!

Thomas R. Holtz, Jr.
Vertebrate Paleontologist
Dept. of Geology
University of Maryland
College Park, MD  20742
Email:Thomas_R_HOLTZ@umail.umd.edu (th81)
Fax: 301-314-9661
Phone:301-405-4084