Seasonal energetics of opossums (Didelphis virginiana) in Ohio.

1. Female opossums acclimatized to each of the four seasons were not significantly different (P greater than 0.05) in oxygen consumption at a Ta of 0 degrees C; the overall average was 0.66 +/- 0.1 ml O2/g-hr. 2. Body weight decreased by 27% from autumn to spring; pelage density increased in winter, but thermal conductance changed very little between seasons. 3. Respirometry revealed no evidence of thermoregulatory adjustments in opossums acclimatized to winter in Ohio.