Dinosaurs 'neither Warm Nor Cold Blooded'

[Oxytropidoceras]

Not too fast, not too slow: Researchers untangle

energetics of extinct dinosaurs. Phys.Org

http://phys.org/news/2014-06-mesothermy-mesozoic-untangle-energetics-extinct.html

Dinosaurs 'neither warm nor cold blooded'

by Jhnathan Webb, BBC News, June 12, 2014

http://www.bbc.com/news/science-environment-27794723

The paper is:

Grady, J. M., B. J. Enquist, E. Dettweiler-Robinson,

N. A. Wright, and F. A. Smith, 2014, Evidence for

mesothermy in dinosaurs. Science vol. 344, no. 6189,

pp. 1268-1272. DOI: 10.1126/science.1253143

http://www.sciencemag.org/content/344/6189/1268

Yours,

Paul H.

[Phillip]

Read this earlier, pretty interesting. I believe there are a few animals alive today that are in between... White shark is one of them.

[Oxytropidoceras]

Go see:

Maybe Dinosaurs Were A Coldblooded, Warmblooded Mix

by Christopher Joyce, All Things Considered, NPR, June 12, 2014

http://www.npr.org/2014/06/12/320803925/maybe-dinosaurs-were-a-cold-blooded-warm-blooded-mix

About animals that combine warmblooded and coldblooded

traits, Christopher Joyce states:

“The echidna is one — a mammal that looks like an anteater

and lays eggs. The leatherback turtle is another. And so are

two of the biggest, fastest predators in the ocean: the great

white shark and the tuna.”

Echidna - https://en.wikipedia.org/wiki/Echidna

Yours,

Paul H.

Edited June 13, 2014 by Oxytropidoceras

[Paleoworld-101]

Interesting article indeed, but I wonder where exactly the transition was made from being mesothermic to fully endothermic like modern birds.

Could the non-avian Maniraptoran dinosaurs have been endothermic too?

I read in another article on this paper too that the author said if dinosaurs were around today competing with endothermic mammals they would probably lose out, which I find a bit contradictory considering how mammals barely progressed beyond small nocturnal forms throughout the entire Mesozoic era. The reason of course being the presence of dinosaurs, which did outcompete them for around 150 million years.

Edited June 13, 2014 by Paleoworld-101

[Auspex]

I see no reason to believe that Ornithischia and Saurischia should necessarily share heat-management systems, nor for even Sauropodomorpha and Theropoda to do so.

[Paleoworld-101]

I don't necessarily disagree Auspex but one thing that to me throws a spanner in the works is that if one group, say theropods, were endothermic and ornithopods or another herbivorous clade were mesothermic that would put the prey at a serious survival and evolutionary disadvantage. They would be less active and vulnerable to attack by more agile, energetic carnivores. The evolutionary arms race between predator and prey results in both trying to out-do the other but if one was endothermic and one was mesothermic, I think the race would be over. If the theropods were mesothermic, then I think the prey can afford to be as well. If either one was endothermic, for the other not to be as well Is somewhat unlikely to occur from an evolutionary perspective where its all about 'survival of the fittest'.

Of course this doesn't factor in the other pros and cons of being an endotherm, mesotherm or ectotherm (namely amount of food consumption needed).

[Auspex]

Ecologically, there is another fulcrum in the checks-and-balances. The efficiency of endothermy increases with the creature's mass, but is strongly constrained by the available food resource. Consider that it takes ten pounds of prey to make one pound of predator, and it becomes clear that the cap is more rigorously 'enforced' against carnivorous endotherms, whereas herbivorous ectotherms have a diminishing ratio of required energy intake with increasing body mass, to the point of needing less external heat income to maintain adequate internal temperature.