Homeostatic competition between food intake and temperature regulation in rats.

Rats obliged to leave a thermoneutral box to feed at air temperatures (Ta) of 25 degrees, 5 or -15 degrees C reduced the total time spent feeding and the duration of each meal as Ta fell, but increased their food intake by eating faster. Increasing the palatability of the food offered at -15 degrees C Ta did not prolong feeding but further increased food intake and the speed of eating. The estimated maximum fall in rectal temperature during feeding at -15 degree C was small (0.48 degrees +/- 0.15 degrees C, S.E.) but skin temperatures of ears and tail tip fell to near 0 degree C. These rats were able to maintain near-normal balances of food intake and body temperature by reallocating the time spent feeding and sheltering and by altering the speed of eating; they thus resolved a conflict between hunger and cold discomfort with little evidence of a strain on homeostasis.