Warm Blooded Or Cold Bloded

Essay by PaperNerd ContributorHigh School, 10th grade August 2001

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Dinosaurs, like other reptiles, were thought until fairly recently to be cold-blooded. There is still a good case for this viewpoint. But lately some scientists have swung to the idea that dinosaurs were warm-blooded. There is a good case for this too. Scientists have conflicting opinions on this subject. Some paleontologists think that all dinosaurs were "warm-blooded" in the same sense that modern birds and mammals are: that is, they had rapid metabolic rates. Other scientists think it unlikely that any dinosaur could have had a rapid metabolic rate. Some scientists think that very big dinosaurs could have had warm bodies because of their large body size, just as some sea turtles do today. It may be that some dinosaurs were warm-blooded. The problem is that it is hard to find evidence that unquestionably shows what dinosaur metabolisms were like.

Clod ""blooded creatures (called ectotherm) rely on factors outside their bodies to maintain their body temperature-factors such as sunlight and shade.

Cold-blooded creatures include fish, amphibians (such as frogs), and reptiles. The view that dinosaurs were cold-blooded includes these evidences: all other living reptiles are cold-blooded, large plant-eating dinosaurs (called herbivores) would have had trouble finding enough food to sustain them. That is because warm-blooded creatures eat 10 times as many calories or joules as cold-blooded creatures of the same size. Warm-blooded creatures today have nasal membranes that moisten and warm the air they breathe, as well as retaining some heat from the air they breathe out. Dinosaur skull fossils don't seem to have a space for this structure (turbinate cartilage). Some dinosaurs from China appear to have had lungs like a crocodile's. They would have been unable to achieve the high rate of air exchange that a warm-blooded animal would need. No dinosaur has been found conclusively...