Behavioral variation among Fox Squirrel (Sciurus niger) populations in urban environments

Abstract Urbanization presents a myriad of challenges to wildlife, yet some individuals or species persist and even thrive in urban environments. Specific behavioral traits that have been proposed to enable animals to cope with challenges and frequently observed in urban wildlife populations across many taxonomic groups include changes in docility, activity, boldness, sociability, and aggression. We conducted a series of standardized behavioral assays to test the hypothesis that urbanization favors these traits in fox squirrels (Sciurus niger), a species that is widespread in urban areas. Based upon previous studies, we predicted that squirrels would exhibit higher levels of boldness, activity, and aggression and lower docility in urban areas with higher human density compared to their counterparts in areas with lower human density areas. We instead found a trend of higher sociability—but not aggression—in squirrels at higher human density sites over lower human density sites, and no differences in docility, boldness, or activity. Our results indicate that the behavior of fox squirrels does not vary dramatically on a fine scale of human density, apart from a trend in heightened sociability in higher human density urban environments.