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Re: PLEUROCOELOUS VERTEBRAE IN SAUROPODS



Everyone seems to be focusing on thermal conduction, but solar radiation
plays a major part in heating a body -- you will overheat far more quickly
on a hot day if you are in the sun than if you are in the shade, regardless
that the ambient air may be the same temperature in both places; also, the
inside of a car will be much, much hotter if the car is in the sun rather
than in the shade.  So the answer to question 1 will be a resounding yes if
the animal is forced to stay in the sun during the heating period (unless
the animal has a completely reflective surface -- and this effect will
reduce with the size of the animal, but at the same rate as heat
conduction).

Van
----------

> From: Stan Friesen  <swf@ElSegundoCA.NCR.COM>
> To: dinosaur@usc.edu
> Subject: Re: PLEUROCOELOUS VERTEBRAE IN SAUROPODS
>
>  > From: "Jonathan R. Wagner" <znc14@ttacs1.ttu.edu>
>  >         1: Does heat loss progress at a different rate than heat gain,
>  > ceteris paribus?
>
> Probably, if for no other reason than that the specific heat of air
> is quite different than the specific heat of flesh (and bone). I
> beleive the specific heat of flesh is not too far below 1.  I rather
> suspect that the specific heat of air is well below 0.5. (I haven't
> had time to check the exact figures, but flesh, being mostly water,
> should have a specific heat close that of water, namely 1, and water
> is said to have a rather high specific heat).
>
> Also, the shifting of the blood supply would change the effective
> specific heat somewhat, as well as changing the rate of temperature
> change at the surface. (With blood flowing to the surface from the
> interior, the surface temperature will change much slower than if
> surface blood flow is reduced).
>
> Also, see the answer to question #2.
>
>  > If so, is it possible to guesstimate a ballpark figure of
>  > the coefficient for a big sauropod?
>
> This depends not only on the actual specific heats, but also on the rate
> effects of blood flow, and relative temperatures.

<snip>