New approaches dinosaurs as climatic proxies

Attempts were being made to investigate the degree to which fossils could be used to reconstruct climates in the ancient world. It is widely recognized that endotherms (basically mammals and birds) are not particularly good indicators of climate because they are found everywhere, from equatorial to polar regions. Their endothermic physiology (and clever use of body insulation) allows them to operate more or less independently of prevailing climatic conditions. By contrast, ectotherms, such as lizards, snakes, and crocodiles, are reliant on ambient climatic conditions, and as a result they tend to be found mainly in warmer climatic zones.

Using this approach to examine the geographic distribution of obvious ectotherms and endotherms in the fossil record proved useful, but then threw up several interesting questions. For M example, what about the immediate evolutionary ancestors of | endothermic mammals in Permian and Triassic times? Were they £ also able to control their internal body temperatures? If they did, how would it have affected their geographic distribution? And more pointedly in this context, dinosaurs seemed to have a wide geographic spread, so did this mean that they were capable of controlling their body temperature rather like endotherms?

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