Re: Saoropod cooling

["David Marjanovic" <david.marjanovic@gmx.at>]

>    If the problem with endothermy is the possibility of heat stroke, an
> alternate question is what is needed to prevent it.  Gregory Paul, I think
in
> personal correspondence, indicated that the body of a camel (a long neck
> mammal) can get warmer, 113 degrees if I remember.

1. How much is this in °C?
2. Is it correct that Fahrenheit used his own body temperature as 100 °F?

> Cooling the key parts is
> the essential.  If that is the brain, then how can this occur.  Again, in
a
> warm, body temperature environment, the only means of cooling is
evaporative,
>  changing the physical state of water to gas to absorbs heat.  An
evaporative
> cooler (moist surfaces, near or around the brain or blood vessels leeding
to
> it placed in the air intake passageway) cooling the head/brain only [...]
makes
> sense to me.  Is there evidence for this in an Ostrich?

I don't know, but I have read in a pop-sci book that the large nasal
cavities of African antelopes and probably iguanodontians serve exactly this
purpose. It's also easy to imagine the enormous noses of ceratopsians being
used that way.

> while
> letting the rest of the body heat up (and aiding growth or digestion?),

Leads to denaturation of some vital proteins = death above AFAIK 42 °C. Up
to this temperature, however, you're probably right. Additionally, fever is
also an important weapon of the immune system.

>    I like to think that a large brained or short necked body needs a more
> constant body temperature as there is little opportunity for cooling the
> blood before it gets to the brain.  I have no evidence to offer to support
> this.  Does this mean a long necked animal is more likely to become
gigantic?
> (or one with good head cooling features)

Or vice versa. All sauropodomorphs have long necks.

>    As an aside,  If an endothermic sauropod in a hot environment uses
> evaporative cooling and lives in a relatively dry climate, obtaining water
> would be important, especially in a draught.  I picture digging for water
> with the toe claws.  In fact, I think this is the primary reason that a
> sauropods foot does not look like that of an elephant but has a few
outcurved
> claws.  I have not seen this written on in any illustration and do not
know
> if it is a new theory.  If any of you artists out there ever want to make
my
> day.....  I would appreciate it.

Good idea; however, I'd love to know how much water birds lose. It seems to
me that there is some evaporative cooling in the air sacs, and the water is
regained in the nose. Anyway, elephants have tusks for digging and so don't
need claws.

> Mark "can not draw" Shelly

David "believes he can, but hasn't tried for over a year, so has no
practice" Marjanovic :-)