A huge marine mammal known as Steller’s sea cow once lived in the waters around Bering Island off the coast of Siberia. It was described in 1741 by Georg W. Steller, a naturalist who was among the first Europeans to see one. In 1768 the animal became exti

Generally speaking, the reading passage has proposed three pieces of hypotheses as the explanation of the extinction of Steller's sea cow living around Bering Island. The lecturer, nevertheless, remains skeptical to the accuracies in each piece of hypothesis, asserts that the evidence given in the passage is not adequate and reliable at all.

Initially, the reading claims that the sea cows may have been over hunted by native Siberian people presenting that sea cows were a good source of food in harsh environment. On the contrary, the lecturer considers this idea untenable presenting that Steller’s sea cow is a massive mammal which can feed a group of people. Sea cows living in the waters around Bering Island were enormous while the population of native people is relatively not very large. There is no need for them to hunt a lot of sea cows. Thus, this theory is unlikely to be true.

Additionally, according to the passage, the extinction may be caused by the sea cows’ main food resource shortage result from ecosystems disturbances. Nonetheless, the professor casts doubt on this theory by saying that if the ecosystems disturbances really had happened, not only sea cows but also a variety of species such as whales may be affected. Yet, scientists never find records of decline in the number of whales.

Ultimately, the reading accounts the extinction to fur traders who were recorded of catching sea cows and possessed weapons that allow them to kill a large number of animal. The lecturer, yet, opposed to this speculation by explaining that the number of sea cows was already low before the traders arrived. Therefore, the number of sea cows see great decline ahead of fur traders beginning to hunt them. Hence, this hypothesis is not convincing.