Were dinosaurs warm blooded? The bones point to yes. (+video)
Studies of growth lines in bones cast into doubt the belief that dinosaurs were cold-blooded, researchers say.
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Sauropods were the only dinosaurs where researchers haven't seen growth lines similar to those of ruminants. Previous studies of their teeth indicate they would have had high body temperatures as well, though they might have been big enough for their mass to generate that heat — what researchers call a "gigantotherm." Researchers don't know what their growth lines would have looked like, since no animals alive today are gigantotherms.Skip to next paragraph
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This indicates that "dinosaursalso had very fast growth rates and needed to eat a lot and maintain high generation of heat internally," Kohler said, so they were most likely warm-blooded.
The theory that dinosaurs were warm has been gaining traction in the last few years in multiple fields, but the researchers admit that other, non-bone-based arguments for cold-bloodedness still stand. Endotherms should have the physical ability to move quickly, and lung volume to pump oxygen to muscles needed for running, which researchers can't be sure dinosaurs had.
"There are a lot of arguments in favor and against endothermy in dinosaurs," Kohler said. "It could be that they have some traits that are clearly endothermic," but others may be muddled.
The study was published today (June 27) in the journal Nature.
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