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

From: John Conway <john_conway@mac.com>
Reply-To: john_conway@mac.com
To: dinosaur@usc.edu
Subject: Re: How Did Hadrosaurs Survive? (Was: Hadrosaur "mummy" questions)
Date: Sun, 27 Oct 2002 04:48:41 +1100

On Sunday, October 27, 2002, at 12:55 AM, Tim Donovan wrote:

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

We do not know how fast tyrannosaurs could run, and we do not know how fast hadrosaurs could run. Short legs does not = slow.

It is logical, and lambeosaurs were also relatively bulky.

Besides, the important thing for predator is MATCH it's prey's speed, so that it can aim it's bite.

But first it must catch up to the prey, which requires faster speed, as the prey was likely to sense the approaching hunter and had a head start. The tyrannosaur could have slowed to match the prey's speed once it had caught up.

Hadrosaurs _may_ have been
slower, but twisting and turning would make it very difficult for a tyrannosaur to land a bite. Cheetahs don't do that well, despite their superior speed; mostly because of the twists and turns of their prey . Tyrannosaurs would have had incredible inertia, and may not have been able to accelerate/decelerate as quickly as hadrosaurs. Matching the hadrosaurs speed for speed, turn for turn, may have been very tricky.

As for big _Tyrannosaurus_ killing all the duckbills; need I mention the Nemegt? _Tyrannosaurus_, and _Saurolophus_ as the most common multi tonner, as I recall. Think outside of the North America. :-)

I didn't say they killed ALL the duckbills, just those least able to evade them. Indeed the Nemegt is very instructive. Notice that all of the Nemegtian hadrosaurs were of American origin(I suspect the same was true of T. bataar). The native Asian hadrosaurs e.g. the Tsagayan taxa, appear totally gone by the Nemegtian period. Perhaps only American hadrosaurs were adapted to advanced American tyrannosaurs, which entered Asia with them.

John Conway, Palaeoartist

"Do I contradict myself? Very well, then I contradict myself, I am large, I contain multitudes." - Walt Whitman

Systematic ramblings: http://homepage.mac.com/john_conway/
Palaeoart: http://homepage.mac.com/john_conway/_palaeoart.html

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