Religious Beliefs. The central myth of the Sirionó is about Dshyási, the Moon, who, after confiding his son to the care of the primordial ancestors of the Sirionó, discovered that they had not taken care of the little boy and that the jaguar had killed him. Full of indignation, he decided to leave them and to no longer give them the animals he hunted. Before leaving he became a culture hero by establishing the institutions of Sirionó society and by becoming the model of ethical hunting behavior.
In the mythical universe there are four entities that, although defined to a certain extent—mainly by their names—tend to blend into each other. They are the éinge (soul); the abatshyekwáya (lit., "who is it that remains unseen?"), a primarily evil being; the etshiróke ("the peeled one"); and the kurúkwa ("he lunges forward with blows"), referring to the Ayoreo whom in the past they perceived as having a mythical aura. As in the case of important game animals, it is important not to destroy or leave behind the bones of a deceased person, especially not the all-important cranium. The body used to be exposed on a platform until the flesh had decomposed; then the bones were recovered and brought back to the village.
Religious Practitioners. Initiation ceremonies for young people of both sexes and separate scarification rites are conducted by old men and women.
Ceremonies. There is a circular dance, which men perform either alone or with women. Embracing one another, the dancers sing monotonously as they look up to the moon. One objective of the dance is to keep illness away and to make people "lighter." The dance also recalls the mythical age when Moon walked on earth and protected the first people.
Arts. Artistic expression is extremely limited. The most distinctive items are feather ornaments worn on the head.
Medicine. The Sirionó believe that an individual is healthy when he has "strength." Health is maintained by morning baths during the cold season, by avoiding the sun's rays and heat, and by performing periodic scarification. Illness is attributed to violations of food taboos, as well as to sun and heat, moon and cold, insects, wind, and shade. In a society without shamanism, illness is treated with scarification and a limited pharmacopoeia.
Death and Afterlife. Death was instituted by Moon after he left the primordial people. There is no land of the dead, and a "fleshless soul" wanders through the forest demanding that its bones receive proper care. A traditional complex funerary ritual involved a series of preventive measures prior to expiring, mourning, placement of the body on a mortuary platform, recovery of the bones, and readjustments after death. The influence of the Catholic church and Evangelical missions has modified the traditional funerary ritual in many ways, the most notable being the imposition of earth burial.