Whether the dinosaurs are endotherms ?

The issue that is being discussed in the reading passage as well as in the lecture is whether the dinosaurs were endotherms. Endotherms are those animals who maintain a constant body temperature under all circumstances. They maintain a specific internal body temperature. The points discussed in the reading passage and the lecture contradict each other and can be discussed in the succeeding paragraphs.

Firstly, it is stated in the passage that as the dinosaur fossils have been discovered in the polar regions, it is clear that they could maintain their body temperature even in such extremely cold climatic conditions, so the polar dinosaurs were endotherms. But, in contrast it is stated in the lecture that the temperature of the polar regions used to be much warmer than it is today, that is, the climatic conditions have changed over time. Moreover, it is possible that the dinosaurs migrated to some warmer places during the cold climate of the region or they went into hibernation that other reptiles do in cold seasons.

The second evidence that is provided in the passage is the connection between the endothermy and leg position and the body movement. The high energy endotherms permitted such activities like running and this activity could be possible if and only if the legs of the dinosaur are underneath its body. While it is described in the passage that high energy endotherms did not only mean that it was for the running purpose. Rather, it supported more weight. Their size could increase hugely and a huge size was advantageous for the dinosaurs.

Moreover, the third evidence is regarding the relation between the endothermy and the bone structure. The bones of endotherms usually include Harvesian canals that house nerves and blood vessels that allow the animal to grow quickly under any circumstances and these canals were present in dinosaurs. But as said in the lecture the dinosaurs also had growth rings that is the thickening of the bones. These grew much slower in cooler periods rather there was no growth. So, there were periods following rapid growth, then no growth, followed again by rapid growth. But the condition should be such that there should be rapid growth even in cooler periods.

Due to all theses contradictions, it could not be proved with certaininty whether the dinosaurs were endotherms .