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Re: Haversian systems in lizards (seriously folks)



Philidor11@aol.com wrote, quoting a US News article:

<"Can you imagine if a herd of brontosaurs were endothermic?" asks
Frank Paladino, a physiologist at Indiana-Purdue University. "They
would have eaten through North America in a couple of weeks." The
problem would have been worse for endothermic carnivores, for, as
James Farlow of Indiana-Purdue notes, "there's a lot less meat on the
hoof than plant on the stem.">

  I wonder who actually put the quote foreward, here. This is Farlow's
bit, and I totally agree with him. However, be wary of trying to say
that if giant sauropods were not fully tachymetabolic, this does not
mean that smaller sauropods or giant carnivores were "cold-blooded"
(hate that term).

  The size of the Madagascar titanosaurs, *Amargasaurus*, and many of
the basal sauropods, were very small, relatively elephant-sized or
thereabouts, and while it is true that *Mammuthus primigenius* had his
woolly coat in a very cold climate, do not doubt that he had the coat
to begin with and was quite huge and massive.

<In an ingenious experiment, Owerkowicz gave cold-blooded monitor
lizards regular treadmill workouts and then compared their bones with
those of nonaerobicized contemporaries. The well-exercised group
showed the same kind of complex channels characteristic of mammals,
birds, and de Ricqlès's dinosaurs, suggesting that Haversian canals
are causally linked to an active lifestyle rather than warm
bloodedness.>

  What he should have done was put the monitors on treadmills in
various environments, and even waited a little while after taking bone
samples. I agree with The Lizard (Zenlizard) in that the experiment
was a mock up of a control environment. Give these animal a
mammal-like lifestyle, and they'll act like mammals. What does this
prove? You can push an animal to extremes reached for if you want. Did
time revert the Haversian canals to normal bradymetabolic moniter
amount and size?

  He (Owerkowicz) almost surely knew (though I am proof-less) that the
reptiles would be metabolically changed by the experience, due to
countless experiments in the wild and simple observation of crocs and
monitors chasing their prey down (on the hoof, so to speak). This is,
by now, almost popular knowledge. It certainly is known in my small
town outside of the general scientific community.

  For a while, I lived in southern Florida, and could not shake the
scene of a dashing crocodile running you down on a bike (this did not
happen to me, but to someone in the next town over, Jupiter, to where
I lived in West Palm Beach).

  And I guess we all know about Ruben et al.'s subjects concerning
their "proof", and no, I'm not putting them down, but the article.

==
Jaime A. Headden

Qilong, the website, at:
http://members.tripod.com/~Qilong/qilong.html
---
All comments and criticisms are welcome!

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