The reading and listening discuss the extinction of the enormous marine mammal "Steller's sea cow" near Berling Island of Siberia.

The reading and listening discuss the extinction of the enormous marine mammal " Steller's sea cow" near Berling Island of Siberia. The article states three theories to describe the reasons for the disappearance of the sea cow- overhunting theory, kelp theory, and traders theory. However, the lecturer refutes the three theories and claims that extinction cause is unknown, and there is a problem with each reason by presenting counter-arguments for each of the assertions. First and foremost, the passage begins by asserting that the sea cow population would have been enormous before the Siberian dwellers had started to hunt them extensively for their food. This claim is challenged by the lecturer. He pointed out that if sea cow had been used as food by Siberian villagers, they would not have needed lots of amounts to result in the extinction. He elaborates this point by arguing that the mammal is humongous about 9 meters long, and tons of weight. In contrast, the population of the Siberian village is not too large, so if they had to hunt on the sea cows they wouldn't have diminished. Next, the professor in the lecture rejects the theory about ecological disturbance by illustrating a couple of facts. First, if something had happened to the supply of the Kelp then other marine species would have affected too. He elaborates this by mentioning the whales that there were no signs of their depletion. Second, kelp growth remained consistent, and no food shortage had observed. These points refute the writer's implication that ecological disturbances would have resulted in a scarcity of kelp that was the essential food source for sea cows. Ultimately, the article wraps its arguments by declaring that there are traces that European fur traders could have caused the depletion, firstly because these possessed weapons to kill, secondly, they were seen to haunt the last sea cow. The speaker in the listening rebuts these points by insisting that the population of sea animals in Berling was already declined before the arrival of Europeans. As their growth was only huge thousand years before 1700, so it is not right to consider European responsible for the problem. He believes that something else had caused the extinction other than the reasons explained.