The concept of the shaman has cross-cultural validity, remecting common patterns of behavior associated with spiritual healing practices found in foraging societies worldwide. The empirical characteristics associated with these practices are examined from evolutionary perspectives and in terms of an evolutionary psychology that identiles their underlying biological bases. The physiological foundations of shamanism are revealed by examining the biological and evolutionary roots for community ritual and the physiological aspects of altered states of consciousness (ASC). Shamanic rituals expanded primate community bonding rituals involving emotional vocalizations and drumming as social signaling and communication processes. The ASC involve the ritual induction of an integrative mode of consciousness that enhanced self-awareness and social identity formation in the concepts of souls and spirits and produced a variety of physical and psychological healing processes. Shamanic practices are part of human nature and involve a variety of evolved capacities that have assisted in human adaptation and survival.