TPO 34

The reading passage proposes three possible theories about why the gigantic Steller's sea cow became extinct. However, the professor in the listening states that all of the theories have problems, and he has proposes sufficient evidence and illustration to these three hypotheses.

As a start, the first theory of the reading article claims that these sea cows became extinct because of the hunting by the native people in the Siberia, and it says that the Siberian people hunted the sea cows as a source of food in the harsh condition. However, the lecturer in the listening contradicts the theory by contending that these animals were extremely massive: nine meters in length and ten tons in weight. Therefore, even though the Siberian people did really hunt them for food, these people only needed one, which could provide the food for months; the people did not require a lot. This negates the first theory.

Next, the second theory in the passage maintains that they became extinct because of the ecology disturbances, which led to the main source of food, Kelp, for the sea cows diminished. On the contrary, the speaker in the listening seriously challenges the theory by pointing out that if the ecosystem really had some disturbances, there must be other declines for other animals, such as whales. Nonetheless, there is no evidence to the decrease for other animals, and this fact refutes the second theory.

Lastly, the reading article has a statement that it is because the European fur traders coming in this island in 1741 by giving the evidence that these people hunted the last sea cow, and led to the extinction. Conversely, the professor questions this theory: at the time the European fur traders arrived, the population of the sea cows had decreased a lot; in fact, the number of the sea cows had reduced for hundreds of years before these people arrived. Accordingly, this theory could not stand to reason.

In sum, although the reading article has proposed three plausible theories for solving the problem of why the sea cows became extinct, the professor in the listening has given strong evidence to argue against these theories.