Are dinosaurs endothermic animal

Animals which stabilizes their body temperature, regardless of environment, are called endotherms, such as birds and mammals. In reading part, it is stated that dinosaurs were endotherms, despite the fact that modern reptiles are not endotherms. On the other hand, listening part disagrees with reading part, by explaining why facts mentioned in reading part – polar dinosaurs, legs’ position, haversian canals – can give us misconception.

The first point is polar dinosaurs. According to the reading part, there were polar dinosaurs in regions which are very frigid, the condition in which non endotherm animals cannot live there due to the fact that they are not maintaining stable body temperature. In contrast, listening part says that those regions could be warmer than we know, and also dinosaurs could have migrated to warmer areas, when it was cold.

Second fact is position of legs in fossils of dinosaurs. Reading part says that having legs underneath the body is a feature, which gives them opportunity to run, of endotherm animals. Listening part, however, it does not necessarily mean that they were endotherms, because they might have this feature due to the fact that they were huge.

The last fact is haversian canals. In the reading part, it is stated that dinosaurs had haversian canals, which gave them opportunity to have sustainable growth, in bones. Listening part, however, says that they had growth rings, which maintained periodic growth. Because of this they stopped growing in cold weather.