Body temperature patterns in black-tailed prairie dogs in the field

Body temperatures (T b ) of black-tailed prairie dogs (Cynomys ludovicianus) were monitored in the field for 1 year. A daily T b rhythm was evident during all months that animals were monitored. Diurnal high T b was always greater than nocturnal low T b . An annual T b pattern was evident with summer T b > winter T b . The maximum range in T b over the year was 5.8 °C, between August diurnal T b (39.3 °C) and January nocturnal T b (33.5 °C). The greatest difference between average high and low T b in 1 month occurred in January (2.8 °C). Torpor was never observed. The lowest recorded T b in any individual animal was 31.0 °C during nighttime hours in January. Males exhibited higher T b than females at all hours during the prebreeding period in January, while females showed greater T b than males during the breeding period in February for 15 of 24 h. Significant differences in T b were not observed between males and females at other times of the year. The daily and annual T b patterns observed result in energy and water savings.