Did you know that North American red squirrels (Tamiasciurus hudsonicus) announce territorial ownership by making vocalizations called rattles? Recently, a study found that short-term stress from capturing and handling squirrels affected acoustic structure of these vocalizations. This research reveals that rattles may also carry important information about squirrel physiological condition.

Sketch contributed by Rachael Coon and fact contributed by Lindsey Broadus

Source: Sehrsweeney, M., Wilson, D. R., Bain, M., Boutin, S., Lane, J. E., McAdam, A. G., & Dantzer, B. (2019). The effects of stress and glucocorticoids on vocalizations: a test in North American red squirrels. Behavioral Ecology, arz044, https://doi.org/10.1093/beheco/arz044