TOEFL integrated writing: Endotherms

The listening casts serious doubts on the reading passage and says that many scientists don’t believe in the evidence that dinosaurs were endotherms.

First of all, the listening passage refutes that polar dinosaurs were endotherms and says that polar dinosaurs when they lived in polar region and their fossil have been found are much warmer than today. The lecture further says that during the months of cold, dinosaurs could have been migrated to warmer areas or hibernated like many reptiles do.

Another argument is that that the legs of the dinosaurs were not underneath the body which can help them for running which shows that dinosaurs were not endotherms because the dinosaurs have much larger body and more body weight and there is no need for dinosaurs keep their legs underneath the body. So, there is no connection between endothermy and the position and movement of the legs of dinosaurs.

Lastly, the lecture says that it is true that many dinosaurs have harversian canals but dinosaurs bones have growth rings which helps in thickening of the bone that indicate that dinosaurs were not rapidly growing. They grew more slowly during cooler periods. The animals who grew quickly or rapid growth or no growth and then rapid growth again were not the characteristics of endotherms.