Abstract: Although fight-or-flight may characterize the primary physiological response to stress for both males and females,females’response are more marked by a pattern of “tend-and-befriend”. Behaviorally, tending involves nurturing activities designed to protect the self and offspring that promote safety and reduce distress, befriending may help to create and maintain social networks .The biobehaveoral mechanism of tend–and-befriend pattern is oxytocin, endogenous opioid mechanisms and estrogen. This previously unexplored stress regulatory sys tem has manifold implications for the study of stress.

Key words: biobehavior, stress, tending-and-befriend, fight-or-flight, neuroendocrine