Re: DINOSAUR digest 638

["Jaime Headden" <jaemei@hotmail.com>]

I wrote:

<<Dromaeosaurs, it seems, may not have been the great runners they have 
been made to be in the past, it's been said (not saying it's true). The 
long tail is quite stiff, and seems to have had one major purpose: to 
stick out.>>

Martin Human wrote:

<Perhaps dumb, certainly uninformed:>

Very informed.

<What are kangaroo tails like, they're pretty stiff aren't they?>

  Not as stiff as most would think (no insult to you, Martin, and this 
is not inteded at you) but more flexible than a dromaeosaur's tail is, 
lacks haemal arches, and curves up in a natural arc, or bends around on 
it's entire length (arc-style) than bending at on point.
 
<I do not see these posing an agility problem for a predator either.
Kangaroos are pretty agile, from the films I've seen.>

  Very agile. Kangaroos have excellent balance, the flexible tail, and a 
sort of counterbalancing system when hopping, where the short forearms 
act as the halters of a insects wings, or like your arms when you walk, 
where left arm moves in the opposite direction of the left leg. But 
that's diverging.

  Of course, all you Aussies out there who can observe a kangaroo in the 
wild will probably disagree with me, uneducated as I am ... :-)

  The function of the kangaroo's tail, though, is to counterbalance (or 
whatever the term is) it's hop, while allowing it to be able to "tripod" 
once in a while. Dromaeosaurs didn't need to tripod, but we've discussed 
the hopping-bit before, and we need to know exactly what osteological 
features are associated with hopping. As far as I can tell, very long 
mt's and short toes are requisite, and dromies lacked these.

  Not to say Dromaeosaurs hopped! :-)

Jaime A. Headden

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