Removal of Harderian exudates by sandbathing contributes to osmotic balance in Mongolian gerbils.

Whittow [18] has inquired whether any animal can limit insensible perspiration through the integument. Sandbathing by the Mongolian gerbil may be a behavioral mechanism to such effect. Ordinarily, Harderian exudates from the external nares of the nose are spread over the pelage by autogrooming and are removed by sandbathing. Several experiments were designed to explore the hypothesis that removal of Harderian materials from the pelage by sandbathing aids osmoregulation through lowering rate of insensible perspiration. An initial experiment showed body weight losses during water deprivation were greater in intact than in Harderianectomized (Hx) gerbils when neither group could sandbathe, but were equivalent when sandbathing was allowed. Subsequent work indicated that variation in relative humidity was associated with magnitude of the difference in weight loss during water deprivation between intact and Hx gerbils, while change in the ambient temperature was not. Checks on these findings showed (1) that nonthirsty intact and Hx gerbils do not differ in amount of internal water and (2) that grooming water losses probably are equivalent in intact and Hx gerbils.