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Re: Sauropod Energetics (Peristaltic pumps for arteries?)



About 5.5 meters, according this reference:

http://en.wikipedia.org/wiki/Giraffe

A 5 m tall giraffe has a heart-head distance of a
little over 1.5 m, and a systolic blood pressure of
~210 mm Hg:

http://compphys.bio.uci.edu/hicks/R629.pdf

Interestingly, in mammals blood pressure scales
positively with body mass, but in birds blood pressure
is independent of body mass:

http://www.journals.uchicago.edu/PBZ/journal/issues/v73n4/990118/brief/990118.abstract.html

For example, a house sparrow has a systolic blood
pressure of 180 mm Hg, while the systolic blood
pressures of an ostrich and emu are 191 and 149 mm Hg.

A 5 m tall giraffe has a total gravitational pressure
of 370 mm Hg.  According to Kent's estimations the
total gravitational pressure in Apatosaurus and
Diplodocus would have been similar, since the maximum
height each could achieve would have been 5-6 m and 4
m, respectively. Giraffe-like cardiovascular
adaptations would have worked quite well for such
sauropods, and do not require hypothetical adaptations
which have not been documented to exist in any extant
vertebrate. 

Guy Leahy


--- "Richard W. Travsky" <rtravsky@uwyo.edu> wrote:

> On Wed, 25 Jan 2006, Guy Leahy wrote:
> 
> > The following article discusses why such a
> solution to
> > high blood pressures in rearing sauropods is
> unlikely:
> >
>
----------------------------------------------------------------
> > Proceedings: Biological Sciences
> > ISSN: 0962-8452 (Paper) 1471-2954 (Online)
> > Issue: Volume 267, Number 1455 / September 22,
> 2000
> >
> > Pages: 1883 - 1887
> > DOI: 10.1098/rspb.2000.1225
> > URL: Linking Options
> > Hearts, neck posture and metabolic intensity of
> > sauropod dinosaurs
> >[...]
> 
> So, how big can a giraffe get? What's the biggest
> one on record?
> (since they're about it for something analogous)
>