Re: Cold-blooded vs. warm-blooded

[Kendall Clements <k.clements@auckland.ac.nz>]

Re: current thoughts about whether dinosaurs  were warm- or 
cold-blooded

Dear Barbara

Each year I run a graduate seminar on dinosaur thermophysiology. I've 
just pasted in the relevant sections of introduction and the reading 
list, which should be FAIRLY up to date. Hope this helps! My 
interpretation of the most recent work is that dinosaurs were probably 
unlike any extant group in terms of metabolism. Furthermore, it's 
possible (if not likely) that dinosaurs did not all share the same 
physiology.


Dinosaur thermophysiology


Over the past 20 years there have been three major ongoing debates in 
the dinosaur literature: avian relationships, causes of dinosaur 
extinction, and dinosaur thermoregulation. Up until the 1960s dinosaurs 
were generally assumed to have had an ectothermic, reptile-like 
metabolism.  In the 1960s and 1970s Loris Russell, John Ostrom and 
Armand de Ricql?s presented arguments for a degree of endothermy in 
dinosaurs, and these arguments were championed and popularised by the 
paleontological maverick Bob Bakker (pronounced "Bokker").  In the 
absence of a time machine evidence for dinosaur thermal physiology is 
restricted to the fossil record and analogies to extant animals.  But 
there are many lines of evidence, including comparative anatomy, the 
ecological and evolutionary success of dinosaurs, bone histology, 
predator/prey ratios, fossil distributions, relationships to living 
groups (notably the birds), oxygen isotope composition in fossil bone 
(e.g. Barrick et al. 1997), and most recently, preserved internal soft 
anatomy.

Be aware when you're reading these papers that you may not always get 
the full story. For example, in his review of "The dinosaur heresies" 
Reid (1987) says: "Bakker could have written an objective account of 
the relevant evidence and arguments, and used it to give a balanced 
assessment of what can currently be surmised; but, instead, he has 
written a one-sided study, in which everything appears to support his 
conclusions, and contrary evidence or arguments are either dismissed or 
ignored."

Basic reading list

Barrick, R.E., M.K. Stoskopf and W.J. Showers (1997)  Oxygen isotopes
in dinosaur bone. In: J.O. Farlow and M.K. Brett-Surman (eds.) The 
complete dinosaur.  Indiana University Press, Bloomington, pp. 474-490

Benton, M.J. (1991)  Polar dinosaurs and ancient climates.  TREE 6: 28-30

Chiappe, L.M. (1995) The first 85 million years of avian evolution.  
Nature 378: 349-355

Chinsamy, A., and P. Dodson (1995) Inside a dinosaur bone.  Amer. Sci. 
83: 174-180

Farlow, J.O. (1990)  Dinosaur energetics and thermal biology.  In:
D.B. Weishampel, P. Dodson and H. Osm?lska (eds.) The Dinosauria. 
University of California Press, Berkeley, California, pp. 43-55

Farlow, J.O., P. Dodson, and A. Chinsamy (1995)  Dinosaur biology.  
Ann. Rev. Ecol. Syst. 26: 445-471

Fischman, J. (1995) Were dinos cold-blooded after all? The nose knows.  
Science 270: 735-736

Hicks, J.W., and C.G. Farmer (1998)  Lung ventilation and gas exchange
in theropod dinosaurs.  Science 281:45-46 and following letters on pp. 
45-48

Morell, V. (1994)  Warm-blooded dino debate blows hot and cold.  
Science 265: 188

Morell, V.  (1996)  A cold, hard look at dinosaurs.  Discover 17(12):
 98-108

Paladino, F.V., J.R. Spotila and P. Dodson (1997)  A blueprint for 
giants: modelling the physiology of large dinosaurs. In: J.O. Farlow 
and M.K. Brett-Surman (eds.) The complete dinosaur.  Indiana University
 Press, Bloomington, pp. 491-504

Reid, R.E.H. (1997)  Dinosaurian physiology: the case for "intermediate"
 dinosaurs.  In: J.O. Farlow and M.K. Brett-Surman (eds.) The complete 
dinosaur.  Indiana University Press, Bloomington, pp. 449-473

Ruben, J. (1991)  Reptilian physiology and the flight capacity of 
Archaeopteryx.  Evolution 45: 1-17

Ruben, J.A., W.J. Hillenius, N.R. Geist, A. Leitch, T.D. Jones, P.J. 
Currie, J.R. Horner, and G. Espe III (1996)  The metabolic status of 
some late Cretaceous dinosaurs.  Science 273: 1204-1207

Ruben, J., A. Leitch, W. Hillenius, N. Geist and T. Jones (1997)  
New insights into the metabolic physiology of dinosaurs. In: J.O. 
Farlow and M.K. Brett-Surman (eds.) The complete dinosaur.  Indiana 
University Press, Bloomington, pp. 505-518

Ruben, J.A., C. Dal Sasso, N.R. Geist, W.J. Hillenius, T.D. Jones
 and M. Signore (1999) Pulmonary function and metabolic physiology of 
theropod dinosaurs.  Science 283: 514-516

Shipman, P. (1997)  Birds do it...did dinosaurs?  New Scientist 
153: 26-31

Spotila, J.R., M.P. O'Connor, P. Dodson, and F.V. Paladino (1991)  
Hot and cold running dinosaurs: body size, metabolism and migration.
 Modern Geology 16: 203-227

Best wishes

Kendall

----------------------
Kendall Clements
k.clements@auckland.ac.nz