Background: Experimental mice are often single-housed either for an individual analysis (feeding behavior, imag‑ ing, calorimetry) or as a stress paradigm (social isolation) in translational biomedical research. Reports of the influ‑ ence of single housing in rodents are conflicting and may depend on age and duration of isolation. Sex is often not included as a factor. In this study we investigated the effects of 4-week single housing in male and female mice on behavior, body weight, and serum corticosterone levels. Results: Behavioral tests showed no effect on anhedonia and stress coping, anxiety and motor exploration. Social avoidance occurred in both males and females. Regarding physiological effects, single housing did not induce changes in serum corticosterone levels, but reduced body weight gain. Conclusions While some mouse studies of chronic social isolation reported depression-related disturbances, our data suggest that single housing might be not necessarily be too stressful. This is important for animal welfare regula‑ tions and experiments in life science research.

Background: Experimental mice are often single-housed either for an individual analysis (feeding behavior, imag‑ ing, calorimetry) or as a stress paradigm (social isolation) in translational biomedical research. Reports of the influ‑ ence of single housing in rodents are conflicting and may depend on age and duration of isolation. Sex is often not included as a factor. In this study we investigated the effects of 4-week single housing in male and female mice on behavior, body weight, and serum corticosterone levels. Results: Behavioral tests showed no effect on anhedonia and stress coping, anxiety and motor exploration. Social avoidance occurred in both males and females. Regarding physiological effects, single housing did not induce changes in serum corticosterone levels, but reduced body weight gain. Conclusions While some mouse studies of chronic social isolation reported depression-related disturbances, our data suggest that single housing might be not necessarily be too stressful. This is important for animal welfare regula‑ tions and experiments in life science research.

Background: Experimental mice are often single-housed either for an individual analysis (feeding behavior, imag‑ ing, calorimetry) or as a stress paradigm (social isolation) in translational biomedical research. Reports of the influ‑ ence of single housing in rodents are conflicting and may depend on age and duration of isolation. Sex is often not included as a factor. In this study we investigated the effects of 4-week single housing in male and female mice on behavior, body weight, and serum corticosterone levels. Results: Behavioral tests showed no effect on anhedonia and stress coping, anxiety and motor exploration. Social avoidance occurred in both males and females. Regarding physiological effects, single housing did not induce changes in serum corticosterone levels, but reduced body weight gain. Conclusions While some mouse studies of chronic social isolation reported depression-related disturbances, our data suggest that single housing might be not necessarily be too stressful. This is important for animal welfare regula‑ tions and experiments in life science research.

Background: Experimental mice are often single-housed either for an individual analysis (feeding behavior, imag‑ ing, calorimetry) or as a stress paradigm (social isolation) in translational biomedical research. Reports of the influ‑ ence of single housing in rodents are conflicting and may depend on age and duration of isolation. Sex is often not included as a factor. In this study we investigated the effects of 4-week single housing in male and female mice on behavior, body weight, and serum corticosterone levels. Results: Behavioral tests showed no effect on anhedonia and stress coping, anxiety and motor exploration. Social avoidance occurred in both males and females. Regarding physiological effects, single housing did not induce changes in serum corticosterone levels, but reduced body weight gain. Conclusions While some mouse studies of chronic social isolation reported depression-related disturbances, our data suggest that single housing might be not necessarily be too stressful. This is important for animal welfare regula‑ tions and experiments in life science research.