In the lecture, the professor casts doubt on the reading passage’s idea that hump whales can make use of stars to migrate. The professor asserts that the evidences are all unconvincing.

Firstly, contrary to the belief in the passage that because of high complexity of brains, the whales are intelligent enough to migrate by the stars, the professor insists that other animals, ducks in particular, are also guided by the stars. However, they are not of high intelligence, so there is clear connection between intelligence and the ability of navigation by the stars

Secondly, the author of the passage points out that the whales migrate in straight line, so they must rely on the stars, since no land feature exist in ocean. The lecture, however, notes that other external objects or forces other than the stars might pose an alternative explanation. Since a special substance in the whales’ brains can help them sense magnetic field, they may be guided by the Earth’s magnetic field.

Lastly, opposing the author’s view that when the whales spy-hop, they observe the stars on the sky, the professor contends that this behavior can be attributed to other explanation. The whales might spy-hop to looking for prey, like sharks, rather than gaze the stars or migrate. Moreover, the whales spy-hop in the daytime, when no star can be seen.