Endotherms are animals that maintain a constant body temperature no matter what the external temperature is. Humans are an example of an endotherm because they maintain a constant internal temperature of 37°C independent of external temperatures.

The reading passage and the lecture both question if dinosaurs are endotherms or not. Whereas the author of the reading states that dinosaurs are endotherms the lecturer suggests otherwise. The lecturer casts doubt on the points made in the reading for three reasons. Firstly, the reading states that dinosaurs surviving in the polar regions must have maintained a constant body temperature irrespective of the external temperature like the endotherms. Nevertheless, the lecturer rebuts this argument by explaining that at those times polar regions were much warmer,and in winters the dinosaurs might have hibernated like other reptiles or might have migrated. Secondly, according to the reading, the position and movement of legs underneath the body of dinosaurs suggest that dinosaurs were endotherms. However, the lecturer disputes this point. He says that although legs were present in dinosaurs' bodies they were not meant for high-energy movements like running as endotherms do, but for growing in size. In this context, it can be said that dinosaurs are not endotherms. Finally, the reading claims that like endotherms, canals were present in the bone structure of dinosaurs also. Additionally, the lecturer claims that the bones were not growing during cooler periods which is not a characteristic of the endotherms because of the latter show regular growth and not periodic growth like dinosaurs. In conclusion, although the reading and the lecture are both about the controversy of whether dinosaurs are endotherms or not, the lecturer refutes all the three points made in the reading.