TPO 34

The article states that Steller's sea cow, an enormous marine mammal which had lived in waters around Bering Island in Siberia extinct suddenly in 1768. The author provides three theories about the reasons of this extinction. However, the professor explains that the hypotheses that are mentioned in the reading are not convincing, and refutes each of them.
First of all, the reading claims that one of the main reasons of the sea cows declination is native hunter. The author says that the sea cows population might be decreased in about hundreds of years due to the natives' overhunting. The professor refutes this opinion by saying that as the natives' population were not high and sea cows were huge animals, they did not have much demand for hunting many of this species.
Secondly, the article posits that ecosystems harsh changes might be another main reason of the sea cows' extinction. While, the sea cows' main food source, Kelp, declined, they could not survive and this matter caused a massive declination. However, the professor says that if this statement was true, then the other marine species which eat these foods, like whales, would not have survived too. But there are not any reports which state that the whales’ populations were also declined.
Third, the reading says that another reason of this extinction can be explained by European fur traders who came to the island after 1741 and killed numerous animals by their weapons. It is likely that they had killed most of the sea cows populations and caused their extinction. The professor opposes this point by explaining that the sea cows' population were not high enough in 1741, their population's reduction were started many years ago.