THERMOREGULATORY COMPETENCE AND BEHAVIORAL EXPRESSION IN THE YOUNG OFALTRICIAL SPECIES - REVISITED

The behavioral and physiological thermoregulatory capabilities of newb orn and infant mammals have been studied for over half a century. Psyc hobiologists have noted that the infants of altricial species (e.g., r ats) have physical and physiological limitations such that heat loss o verwhelms heat production, thus forcing a reliance on behavioral therm oregulation for the maintenance of body temperature. Recent evidence, however, suggests that a modification of this view is justified. Speci fically, throughout a range of moderately cold air temperatures es, no nshivering thermogenesis by brown adipose tissue contributes significa ntly to the infant rat's behavioral and physiological adaptations to c old challenge. Given the prominent use of altricial species for the st udy of infant behavior, increased understanding of the infant's physio logical responses to cold and the effect of thermal factors on behavio r is wan-anted. (C) 1998 John Wiley & Sons, Inc.