Question 38·Medium·Inferences
In 2021, behavioral ecologists monitored six island populations of the same fox species. On islands with few daytime-hunting raptors, the foxes were mostly active during daylight; on islands with many such raptors, the foxes were mostly active at night. When twelve foxes were moved from a low-raptor island to a high-raptor island, their activity shifted to nighttime within two weeks. Average temperatures and measures of food availability did not differ meaningfully across the islands.
Therefore, the researchers most likely concluded that the foxes’ daily activity pattern is primarily shaped by _____
Which choice most logically completes the text?
For this kind of SAT Reading & Writing inference question, first identify what the study is testing and what the concluding sentence (the one with the blank) is trying to summarize. Then, quickly underline or note: (1) what clearly varies between the conditions/groups, (2) what was kept similar or explicitly said to be “not different,” and (3) any experimental manipulation (like moving animals). Use these to eliminate answer choices that rely on ruled-out factors or that introduce new, unsupported ideas, and select the option that matches the main variable linked to the observed change.
Hints
Locate the main contrast in the passage
Compare what is said about the islands with few daytime-hunting raptors and the islands with many daytime-hunting raptors. What changes along with that difference?
Pay attention to what was controlled or ruled out
The passage mentions that average temperatures and measures of food availability did not differ meaningfully. How does that affect answer choices that mention those factors?
Use the relocation experiment
Focus on what happened when twelve foxes were moved from one island to another. What does the quick change in their activity pattern suggest about whether the cause is something they are born with or something in their current environment?
Step-by-step Explanation
Clarify what the question is asking
The question asks what the researchers most likely concluded primarily shapes the foxes’ daily activity pattern. This means you must identify the factor the study points to as the main cause of when the foxes are active (day vs. night).
Restate the key findings of the study
Summarize the important details:
- On islands with few daytime-hunting raptors, foxes were mostly active during daylight.
- On islands with many daytime-hunting raptors, foxes were mostly active at night.
- When foxes were moved from a low-raptor island to a high-raptor island, their activity changed to nighttime within two weeks.
- Average temperatures and food availability did not differ meaningfully across the islands.
These points tell you what does and what does not change with the foxes’ behavior.
Use controls to eliminate options
The passage states that average temperatures and measures of food availability were similar across all islands. That means these factors are not good explanations for why fox activity patterns differ.
- Any answer focused on temperature can be eliminated because the text says temperatures did not differ meaningfully.
- Any answer focused on food availability or plant fruiting is also weak because the passage suggests food conditions are roughly the same.
Also note that the foxes changed behavior quickly when moved, in just two weeks, which suggests a flexible response to current conditions rather than something fixed from birth.
Connect the behavioral change to the most likely cause
The only major difference described between islands that matches the foxes’ behavior is the number of daytime-hunting raptors (predators). When raptors are few, foxes are active in the day; when raptors are many, foxes become active at night, and foxes moved into a high-raptor environment rapidly switch to nighttime activity. This pattern shows their daily activity is primarily shaped by immediate predation risk from raptors in the foxes' habitat, which is the correct answer.