In Inca mythology, Mama Pacha or Pachamama is a fertility goddess who presides over planting and harvesting. She causes earthquakes. Her husband was either Pacha Camac or Inti, depending on the source. Llamas are sacrificed to her. After conquest by Catholic Spain her image was masked by the Virgin Mary, behind whom she is invoked and worshiped in the Indian ritual, in some parts of Argentina, Chile, Bolivia and Peru (Merlino y Rabey 1992).
Since Pachamama is a "good mother", people usually toast to her honor before every meeting or festivity, in some regions by spilling a small amount of chicha on the floor, before drinking the rest. This toast is called "challa" and it's made almost everyday. Pachamama has a special worship day called "Martes de challa" (Challa's Tuesday) where people bury food, throw candies, burn incense. In some cases, celebrants assist to traditional priests called "yatiris" in ancient rites to bring good luck or the good will of the goddess, such as sacrificing guinea pigs or burning llama fetuses (although these last two are no longer very common). The festival is after carnival and one day before the Catholic "miércoles de ceniza" (Ash Wednesday).
The central ritual to Pachamama is the Challa or Pago (Payment). It is carried out during all the month of August, and in many places also the first Friday of each month. Other ceremonies are carried out in special times, as upon leaving for a trip or upon passing an apacheta. According to Mario Rabey and Rodolfo Merlino, Argentine anthropologists who studied the Andean culture since the decades from 1970 to that of 1990, "the most important ritual is the challaco. Challaco is a deformation of the quechua words 'ch'allay' and 'ch'allakuy', that refer to the action to insistently sprinkle (Lira 1941: 160 y 161). In the current language of the peasants of the southern Central Andes, the word 'challar' is used like a synonym of 'to feed and to give drink to the land'. The challaco, just as is practiced in the studied area (Merlino y Rabey 1983: 153-155), covers a complex series of ritual steps that begin in the family dwellings the night of the eve, during which cooks a special food, the tijtincha, and that culminate in an eye of water or the beginning of a ditch where is carried out the main ritual to the Mother Earth, with a series of tributes that include food, beverage, leaves of coke and cigars" (Rabey y Merlino 1988.
The religion centered in the Pachamama is practiced currently in parallel form to the Christianity, to the point such that many families are simultaneously Christian and pachamamistas (Merlino y Rabey 1983).