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Re: [Re: ... vs energy efficient gigantothermy (boo hiss)]



The last of it.
_________________

"David Marjanovic" <david.marjanovic@gmx.at> wrote:

> > From: Ecology of the Komodo Monitor
> >
> > "Normal walking and searching is carried on at a speed of approximately
> 4.8
> > km/hr (our observations agree with those of Lederer, 1942)."
> >
> > Work Auffenberg cited:
> >
> > Lederer, G. 1942. Der Drachenwaren (_Varanus Komodoensis_ Ouwens). Zool.
> Gart.
> > (Leipzig), (n.s.) 14 (5/6):227-244
> 
> OOC -- you trust a paper from 1942 that is apparently based on         >
observation in a zoo? This is so old that I didn't even know that The  > Beast
was ever called "Drachenwaran" (the e must be a typo) in German!

++++++++++++++++++++++++++

No, I never read it. I was only citing the paper that Auffenberg cited, which
agreed with his assessment of ora speeds, which were taken in the wild. This
was in response to GSP's original comment that statements in the literature of
5km oras were wrong (admittedly this does agree with his statement, but flat
out disagrees with his statement that they only "plod" along at 1-2km/hr).

So what does "Drachenwaran" (Drachnwaran?) translate to?

_______________________

> > Yes, and these mammals also have anatomical "cheats" that allow them > >
to hold up their large bodies with very little muscle use (e.g. the  > >
locking mechanisms of elephant and ungulate legs). A reptile with    > >
equivalent "cheats" wouldn't find it so hard to hold itself up either.
> 
> This works only in _standing_. Not in walking.

++++++++++++++++++++

True, but free oneself from the aerobic problem of lung compression while
walking and, possibly, lower the cost of locomotion and there should be no
problem. Incidentally, since we are talking about sauropods, would it not make
more sense to have these "cheats" in place if one isn't going to be walking
half as much as they will be standing?

________________________

> > > Because it is not possible for continental animals exposed to      > > >
numerous disease vectors and predators as well as accidents to live > > > more
than 60 years or so, all giant animals must grow rapidly.
> >
> > Though, in general, I agree with this statement, we do have          > >
continental chelonians (_Terrapene_ for one) that regularly reach    > >
centennial years, and giant tortoises (which were also probably      > >
centennial) were once common continental animals as well. So there   > > are a
few exceptions there.
> 
> Turtles are quite immune to predation, aren't they?

+++++++++++++++++++++++++++

I don't know; turtles are weird not only phylogenetically, but ecologically
and metabolically as well. Yeah, _Geochelone nigra_ has reached some pretty
successful sizes and previous giant tortoises were even larger, but the
chelonian shell has been around for some 230 million years. That's an awful
lot of time for predators to find ways around it (tiger sharks saw through
turtle shells, alligators crack'em open, certain raptors drop them from high
heights on rocks). How they can get away with all this and still attain large
terrestrial sizes escapes me.

___________________________

> > At least one species of crocodylian today (_C.niloticus_) has an     > >
erect stance (pers. observ)

> Semi-erect? (Pers. obs. on TV.)

++++++++++++++++++++++++++++++

Completely erect (pers. observ. at Reptile Gardens SD). Are you sure that you
are thinking of Nile's. If you can get a copy of Nova's croc special (with
David Attenborough) there are some nice IR shots of Nile's invading a lying
feast. In those shots one can see the erect stance of the hind limbs (which is
all that matters). Other than that most documentaries on crocs seem to have
this unspoken rule that cameramen can only take facial shots or half-heights
shots of the crocs and full body shots on land are reserved for sleeping,
slipping in the water, or moving a couple of feet in a sprawl.

So I suppose this would be pers. observ. on NOVA :)

Jura


Jurassosaurus's Reptipage: A page devoted to the study of and education on,
the reptilia:

http://reptilis.net

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