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Re: How Did Hadrosaurs Survive? (Was: Hadrosaur "mummy" questions)




From: "Cliff Green" <dinonaut@emerytelcom.net>
Reply-To: dinonaut@emerytelcom.net
To: "dinosaur mailing list" <dinosaur@usc.edu>
Subject: Re: How Did Hadrosaurs Survive? (Was: Hadrosaur "mummy" questions)
Date: Fri, 25 Oct 2002 12:49:23 -0600


> This reminds me of K. Carpenter's 1988 tail bite paper, but the idea
isn't
> credible. Hadrosaur tails were stiffened; if they were incapable of the
> movement required for swimming, defensive use also seems unlikely. Nor did
> the hadrosaurs evolve caudal weapons which would have enhanced such a
> defense.


Dear Tim and list,

I am aware of the tendons running across the backs and tails of
duckbills. I was under the impression that these were used to reinforce the
weight of the bones and muscles. I don't see how this would make the tails
immovable. Tendons have at least some stretch and mobility. Their tail
structure wasn't that similar to the thin, interlocking, balencing beams of
the Dromeosaurs. Perhaps they didn't have the mobility of a dog wagging it's
tail, or for the wide swinging strokes required for swimming, although most,
if not all, modern animals can swim. This didn't mean they couldn't have
used thier tails as weapons. They could use the momentum of swinging thier
hips and back legs. Even with it being stiffened, the tail could still act
as a REALLY big baseball bat.
BTW, My theory has just as much credibility as any one elses, seeing
that, once again, no one has seen

I don't think so; it seems far more likely that hadrosaurs fled, and fought only as a last resort. If hadrosaurs had regularly attempted to stand their ground, weapons and or armor would have been selected for. Instead they evolved keen senses and longer legs, and "hooves".





No
theory can be absolutely proven or disproven on this, intil someone studies
duckbill behavior patterns in the wild.
    On another note, I wasn't insinuating that any known duckbill had tail
weapons.

I know; I was just pointing to the absence of such weapons as evidence for a noncombative survival strategy.



I said that at least one type had large spikes across it's back and
tail. I think these spikes would have made it harder for a theropod to bite
down on a duckbill from above, into the spine.

It would have bitten into the upper thigh or flanks.

I should have been more clear
on this. My apologies.
This all reminds me of one of the recent talks at SVP. Greg Paul was
refuting the newer theories that Brachiosaurs couldn't raise thier heads up
because someone's computer data said otherwise. I think we are all in for at
least a few more surprises when it comes to what animals, extinct or other
wise, could do.


> By running away, but not (all hadrosaurs could escape a new predator
with
> consummate senses and speed.


    I'm afraid you lost me on this one. I presume your word "not" is "no",
but what "New" predator are you talking about? Are you saying that
tyrannosaurs were a newly indroduced species to the West,

Tyrannosaurus or its immediate ancestor appears absent in the lowlands in the late Edmontonian period and probably evolved in the well inland environments, perhaps in response to Alamosaurus, as Starkov suggested. By the Lancian period it had spread to the lowlands, apparently eclipsing several taxa least able to fight or flee.



in the Late
Cretaceous, like Bakker's utahraptor immigration theories in "Raptor Red"? I
thought Stokesosaurus from the Morrison was considered a primative
tyrannosaurid. Please enlighten me.


Sincerely,

Cliff Green


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