Fat and happy in the city: eastern chipmunks in urban environments

Cities are rapidly expanding, and wildlife may experience different selection pressures in urban environments when compared to natural habitats. Phenotypic differences between urban and natural populations may occur because of the altered urban environment. Behavior, the activity of the hypothalamic-pituitary-adrenal (HPA) axis and body condition can be expected to differ between urban and natural habitats. We used the eastern chipmunk (Tamias striatus) to test for differences in behavior assayed from an open field test, hair and fecal cortisol concentrations, and body condition (size-corrected body mass), predicting that urban chipmunks would exhibit more exploratory behavior, higher cortisol concentrations, and higher body condition, than their counterparts from natural habitats. We sampled eastern chipmunks in 2 urban areas paired with natural habitats and subjected adult chipmunks to an open field test, collected hair and fecal samples for the determination of cortisol concentration...