[The effects of fur on the thermal regulation of mice (Mus musculus)].

In order to ascertain the thermal insulation function of fur in mice, food and water intakes and rectal and skin temperatures were observed in Jcl: ICR mice and a group of the same species with their fur clipped, as well as BALB/C nu/+ and nu/nu mice. Food and water intakes increased as the ambient temperature dropped. The rectal temperature remained almost unchanged at ambient temperatures of from 18 to 30 degrees C. Skin temperatures were highest at side of the abdomen, lower at the neck, and lowest at the head. There was a tendency for skin temperatures to increase as the ambient temperature rose. The skin temperatures of mice with fur were higher than those of mice without fur. The thermal insulation of fur was 0.25, 0.14 and -0.06 clo at 18, 22, 26 and 30 degrees C in ICR mice, and 0.36, 0.01, 0.01 and -0.03 clo at 18, 22, 26 and 30 degrees C in BALB/C mice, respectively. These results confirm that heat loss from the skin at low temperatures could be prevented by the presence of fur. It also appeared that the hairless mice mutant had a lower metabolic rate than the animals with their fur clipped.