Body temperature (Tb) was monitored telemetrically in adult deer mice kept in an environmental chamber at low ambient temperature (Ta = 15 degrees C). Mice were challenged with various doses of 2-deoxy-D-glucose (2DG, a glycolysis inhibitor) or mercaptoacetate (MA, a fatty acid oxidation inhibitor) or a combination of the two drugs. A preliminary study suggested that higher doses of 2DG and MA, either individually or together, tended to produce a transient decrease in Tb. In the main experiment, either 2DG or MA or the two drugs together was sufficient to induce a significant, temporary hypothermia. In neither experiment, however, did any treatment affect 24-h food intake or induce daily torpor. The latter outcome contrasts with Siberian hamsters, in which torpor is readily triggered by similar 2DG treatments. Apparently, glucoprivation and lipoprivation resulting from 2DG and MA treatments, respectively, sufficient to produce significant hypothermia, are inadequate to instigate torpor in Peromyscus.