Humans arrived in the Kaliko Islands about 7,000 years ago, and within 3,000 years most of the large mammal species that had lived in the forests of the Kaliko Islands had become extinct. Yet humans cannot have been a factor in the species' extinctions, b

The author in this argument concludes that the climate change or other environment factors have caused extinction of large mammals in Kaliko islands and not by humans. The author make makes unsubstantiated assumptions like humans not being involved in the extinction, assumes all large mammals are extinct and also does not define clearly how the climate and environmental factors led to the extinction of large mammals.

To begin, the author assumes that the arrival of human to the Kaliko island had no reason to believe that led to extinction of large mammals. He further tries to convince by using the evidence of archeologist who found fish bones that been discarded in many sites. He fails to give information about the archeologists or any citations and the bones of fish discarded dates back to the years when humans lived in the island and the time when large mammals became extinct. The author also assumes that since no bones of large mammals are found so the humans did not hunt large mammals and they only used fish. The author is in agreement that the bones of fish had something to do with the human. The evidence from the archeologists has led the author to assume that humans were not involved in extinction of large mammals.

The author makes another assumption that by using ambiguous words like most of large mammals and numerous sites. The term most is not clearly defined by the author he assumes all of the large mammals and does not give a precise number of how many large mammals. The author, also states that bones of fish are found in numerous sites. The author assumes that bones of fish were found arbitrarily in many sites in the islands and does not clearly specify the sites. The author does not define few terms like most and numerous and makes assumptions that all large mammals are extinct and fish bones are found in all sites of islands.

Finally the author assumes that climatic factors or some environmental factors have led to extinction of large mammals and not by humans. The author does not take responsibility in stating specifically what factors whether rainfall, temperature, etc. have caused and how these factors led to the extinction. The author does not think these environmental factors are the reason for the discovery of bones of fish. The author makes a very strong conclusion based on weak evidence like discovery of fish bones at numerous sites and not mammals bones.

The argument can be strengthened by providing evidences about the archeologists, the bones of fish dates back particularly to the time when large mammals became extinct ,clearly defining the terms most and numerous and by stating which climatic or environmental factors caused and how they caused the extinction of environment. However, the argument in the current state that humans had no involvement in extinction of large mammals but the climatic or environmental factors based on the authors assumption is flawed.