Grooming secretions and seasonal adaptations in the blind mole rat (Spalax ehrenbergi)

The postulated thermoregulatory function of grooming in the 'blind' mole rat (Spalax ehrenbergi), a solitary, highly aggressive subterranean rodent, was tested by subjecting individuals to extreme hot and cold environments and measuring their grooming frequency and thermoregulatory capacity. It was found that exposure to heat stress during both the winter and the summer failed to elicit grooming in isolated mole rats, even though their body temperature was significantly elevated. Thus, unlike Mongolian gerbils (Meriones unguiculatus), mole rats do not seem to have a mechanism for lowering body temperature by grooming. However, at low temperatures, grooming behaviour significantly increased during both seasons, although a decline in body temperature was recorded only during the summer. Because grooming in mole rats expresses Harderian lipids onto the fur, it is suggested that in the winter, under cold stress, this behaviour might prevent a drop in body temperature through spreading insulating Harderian lipids.