Naturalist: The recent claims that the Tasmanian tiger is not extinct are false. The Tasmanian tiger’s natural habitat was taken over by sheep farming decades ago, resulting in the animal’s systematic elimination from the area. Since then naturalists working in the region have discovered no hard evidence of its survival, such as carcasses or tracks. In spite of alleged sightings of the animal, the Tasmanian tiger no longer exists.
Which one of the following is an assumption on which the naturalist’s argument depends?
(A) Sheep farming drove the last Tasmanian tigers to starvation by chasing them from their natural habitat.
(B) Some scavengers in Tasmania are capable of destroying tiger carcasses without a trace.
(C) Every naturalist working in the Tasmanian tiger’s natural habitat has looked systematically for evidence of the tiger’s survival.
(D) The Tasmanian tiger did not move and adapt to a different region in response to the loss of habitat.
(E) Those who have reported sightings of the Tasmanian tiger are not experienced naturalists.
A. The exact cause of the final tigers’ extinction isn’t important—what matters is that sheep farming had a significant negative impact. Even if hunters killed the last few, that doesn’t weaken the argument.
B. This would weaken the argument. If tiger carcasses occasionally appeared but were eaten by scavengers, it would suggest tigers may have survived longer than assumed.
C. Negating this doesn’t affect the argument. One naturalist failing to search thoroughly doesn’t meaningfully change the overall evidence.
D. Correct. If this assumption is false and the tigers simply relocated and adapted elsewhere, the argument about sheep farming causing their extinction falls apart.
E. While this would support the argument, it's not required. And like C, its negation—one naturalist reporting a sighting while impaired—has minimal impact.
