RE: Taking the temperature of dinosaurs?

["John Scanlon" <riversleigh@outbackatisa.com.au>]

Note that the Varanus salvator paper Dann linked to concerned a captive
individual in a thermal gradient, meaning a substrate at its preferred body
temperature was constantly available during the study. There are few places
where this would be the case year-round (or even through the growth season)
in the wild.

I think it will be very interesting to apply this 13C:18O method to known
ectotherms from a range of places and times, as it'll provide a whole
'nother dimension to inferences about habitat and behaviour differences
within local faunas (proxy for terrestrial/aquatic/arboreal,
diurnal/nocturnal, heliotherm/thigmotherm) as well as testing/validating the
snake-body-size palaeothermometry approach proposed in the case of
Titanoboa.

Plus one of the coolest things (claimed) in the paper is that the method
allows assumption-free calculation of the environmental delta18O, and thus
takes the average temperature of the habitat as well as growth-weighted
average for the animal concerned. I won't be surprised if it's possible to
distinguish ectotherms and endotherms in many cases, when multiple taxa are
compared within a fauna.

-----------------------------------------------
Dr John D. Scanlon, FCD
Riversleigh Fossil Centre, Outback at Isa
riversleigh@outbackatisa.com.au
http://www.outbackatisa.com.au/Fossil-Education/Palaeontologist.aspx
 
"Get this $%#@* python off me!", said Tom laocoönically.

-----Original Message-----
From: Dann Pigdon [mailto:dannj@alphalink.com.au] 
Sent: 26 May, 2010 11:38 AM
To: dinosaur@usc.edu
Subject: Re: Taking the temperature of dinosaurs?

On Wed, May 26th, 2010 at 11:19 AM, "Thomas R. Holtz, Jr." <tholtz@umd.edu>
wrote:

> It is worth noting that the analysis cannot at present resolve
> endotherms
> vs. ectotherms. It is just a thermometer: it is not a thermometer
> with a
> time component.
> 
> Too many people in the press about this seem to think that
> warm-blooded
> animals actually have higher body temperatures than cold-blooded
> ones.

Indeed. Some varanids are able to regulate their body temperatures to about
35 C, with a 
precision of +/- 1 C.
http://www.jstor.org/pss/30155835

That's higher than your average monotreme (30-32 C).

-- 
_____________________________________________________________

Dann Pigdon
GIS Specialist                         Australian Dinosaurs
Melbourne, Australia               http://home.alphalink.com.au/~dannj
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