RE: DINOSAUR digest 225

[Miles Constable at Edmn <ConstableM@mail.edm.ab.doe.ca>]

M. Stam requests on Tue, Oct 11
>>------------------------------
>>
>>Date: Tue, 11 Oct 1994 13:11:56 +0100
>>From: jstam@iag.TNO.NL (Jean-Marie Stam)
>>To: DINOSAUR@lepomis.psych.upenn.edu
>>Subject: dinosaur extinction
>>Message-ID: <9410111211.AA27125@iag.tno.nl>
>>
>>
>>My concrete questions are:
>>
>>1) are there still any cold-blooded grasseating reptiles?
>>
>>2) how much food, in relation to its size, would a cold-cblooded
>>reptile need to maintain itself (e.g. a dinosaur of 2000 kg)?
>>
>>Thanks for any help
>>
>>Jean-Marie
>>~~~~~~~~~ J.M.T. Stam; jstam@iag.tno.nl; Delft; The Netherlands ~~~~~~~~

1. All reptiles are cold-blooded (poikilothermic). Many are herbivorous ie. 
iguanas and tortoises in the Galapagos Islands. Whether they eat grass is a 
matter I do not know about, but they eat cacti.

2. A cold-blooded reptile of 2000 kg would not need all that much fodder to 
survive, as their metabolisms are considerably slower than "warm blooded" 
animals.

If you are going to do a thesis on this topic you should spend a 
considerable amount of time reading about warm-blooded and cold-blooded 
physiology and, of course, everything that has been written on the 
physiology of dinosaurs, especially by Bakker and recent research in the 
field. Recent work shows a possible physiology in at least some dinosaurs 
that is a hybrid between poikilothermy and homeothermy. Cross-sections of 
bones indicate that some dinosaurs had bone structure of homeotherms but 
also had annual rings of growth like poikilotherms. So, there is no clear 
cut answer as to their physiology, it is a fascinating area that requires an 
open mind. Good luck.