Other Worlds – Many shamanic cosmologies posit the existence of lands, realms, or dimensions accessible to shamans after initiation and training. These are rarely if ever equivalent to the transcendent realms posited by monotheistic religions (e.g., heaven and hell). They are perhaps best understood as alternative lands, access to which is made by unusual means (for ordinary humans): descent into an underworld, ascent into an upper world, or nonphysical journeys over vast distances. Many of these other worlds are the primary home of significant other-than-human persons, or spirits. Where these include the beings who control animals, birds, or fish in this world, shamans may be responsible (as resource managers) for mediation to ensure that hunters or fishers encounter sufficient prey to meet the needs of their community. Where the otherworld persons control diseases or are “spirits of illness,” shamans’ roles may include seeking powerful aid in healing or mediation to divert the negative attention of predatory beings. Some other worlds are the eventual destination of the dead, in which case shamans are unique in being able to journey there before their deaths and—the important bit—return again. That this is always a dangerous pursuit is illustrated by the need for initiation and the aid of powerful helpers. When shamans form intimate relationships with otherworld persons, it can affect their social standing and role, and even their gender.
Historical Dictionary of Shamanism by Graham Harvey and Robert J. Wallis 2007