DeCoursey and colleagues (2000) compared survival rates of three groups of eastern chipmunks (Tamias striatus): an SCN-lesioned group, a sham-lesioned group, and an intact, control group. They found that
A) activity levels among the three groups were surprisingly unaffected by the experimental treatments.
B) mortality rates due to predation were significantly higher in the SCN-lesioned group than in the other two.
C) the primary cause of mortality was malnutrition resulting from the SCN-lesioned group's failure to spend enough time foraging.
D) the sham-lesioned and the control groups died at higher rates than the SCN-lesioned group, demonstrating the benefit of the surgery for the SCN-lesioned group.

Question

Quizplus · Accepted Answer

The SCN (suprachiasmatic nucleus) is involved in regulating circadian rhythms, which can affect an animal's behavior and its ability to avoid predators. Lesioning the SCN would disrupt these rhythms, potentially making the chipmunks more vulnerable to predation compared to those with intact or sham-lesioned SCN, leading to higher mortality rates in the SCN-lesioned group.

DeCoursey and Colleagues (2000) Compared Survival Rates of Three Groups