History of Life by Cowen Richard

Author:Cowen, Richard
Language: eng
Format: epub
Publisher: John Wiley & Sons, Inc.
Published: 2013-04-18T00:00:00+00:00

WERE DINOSAURS WARMBLOODED?

There are several aspects of this question. First, what does “warmblooded” mean? Did dinosaurs control their body temperature precisely? that is, were they homeotherms? Or were they heterotherms, allowing their body temperature to vary quite widely, depending on their needs? Were they endotherms? did they produce a high body temperature by generating a lot of metabolic heat, raising their overall energy budget? Or were they ectotherms, controlling their body temperature dominantly by behavior, by clever use of sunlight, shade, shelter, activity level, and so on? If they were homeotherms, did they control their body temperature at a much higher level than their average environment, say 35°–40°C (95°–104°F), like most mammals and birds? Or at a lower level, say 30°C (86°F), more like a platypus or a hedgehog? Or was it lower still, hardly any warmer than the average temperature of an equatorial habitat, say 27°C (81°F)? Along with these answers come different estimates of the resting metabolic level, the energy output, and the activity level of dinosaurs. Were they comparable with elephants, ostriches, or lions, or more like living reptiles, or like none of the above? Were all dinosaurs alike in their physiology?

Figure 12.28 Oviraptor, misnamed as an egg thief when actually it was a builder and guardian of its own nests. (Reconstruction by Bob Giuliani. © Dover Publications Inc., New York. Reproduced by permission.)

Download

Copyright Disclaimer:
This site does not store any files on its server. We only index and link to content provided by other sites. Please contact the content providers to delete copyright contents if any and email us, we'll remove relevant links or contents immediately.