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Re: Dinosaurs as "mesotherms"

Ben Creisler

Comments by Greg Paul on the Science website:


On Thu, Jun 12, 2014 at 11:14 AM, Ben Creisler <bcreisler@gmail.com> wrote:
> Ben Creisler
> bcreisler@gmail.com
> A new paper:
> John M. Grady, Brian J. Enquist, Eva Dettweiler-Robinson, Natalie A.
> Wright & Felisa A. Smith (2014)
> Evidence for mesothermy in dinosaurs.
> Science 344 no. 6189: 1268-1272
> DOI: 10.1126/science.1253143
> http://www.sciencemag.org/content/344/6189/1268
> Were dinosaurs ectotherms or fast-metabolizing endotherms whose
> activities were unconstrained by temperature? To date, some of the
> strongest evidence for endothermy comes from the rapid growth rates
> derived from the analysis of fossil bones. However, these studies are
> constrained by a lack of comparative data and an appropriate energetic
> framework. Here we compile data on ontogenetic growth for extant and
> fossil vertebrates, including all major dinosaur clades. Using a
> metabolic scaling approach, we find that growth and metabolic rates
> follow theoretical predictions across clades, although some groups
> deviate. Moreover, when the effects of size and temperature are
> considered, dinosaur metabolic rates were intermediate to those of
> endotherms and ectotherms and closest to those of extant mesotherms.
> Our results suggest that the modern dichotomy of endothermic versus
> ectothermic is overly simplistic.
> **
> Commentary:
> Michael Balter (2014)
> Dinosaur metabolism neither hot nor cold, but just right.
> Science  344 no. 6189: 1216-1217
> DOI: 10.1126/science.344.6189.1216
> http://www.sciencemag.org/content/344/6189/1216.summary
> Paleontologists have struggled for 50 years to determine whether
> dinosaurs were cold-blooded like today's reptiles or warm-blooded like
> most modern mammals and birds. A study on page 1268 examines the
> growth and metabolic rates of nearly 400 living and extinct animals,
> and concludes that neither was right. Instead, dinosaurs had an
> in-between metabolism.
> **
> Blogs:
> http://phenomena.nationalgeographic.com/2014/06/12/dinosaurs-tuna-great-whites-echidnas/