The kayum is a ceremonial drum in the shape of a white clay jar with a wide mouth, used by the present-day Lacandons of the Chiapas rainforest. This instrument has been identified in pictorial sources and in pre-Hispanic murals, demonstrating its historical continuity in certain ceremonies in which it is used alongside anthropomorphic incense burners.
The kayum is placed on a circular base made of vines and is played with the fingers and palms of the hands, striking a deerhide drumhead. In the past, this membrane was fashioned from the skin of the sarahuato monkey, an animal symbolically associated with dancing and singing. The sound of this percussion instrument varies according to the amount of water contained within it.
The kayum occupies a special place in the ritual and symbolic sphere, for it is associated with the god K'ayum (or Kai Yum), lord of song, whose effigy appears on the front of the instrument and gives it its name. The word kayum is also used to designate a singer-musician, or one who “sings and dances at the same time.” This deity is said to be an assistant of Hach Ak Yum, the creator god of the world. According to Lacandon oral tradition, K'ayum is one of the celestial deities who dwells at the archaeological site of Yaxchilán, specifically in Structure 21. His function is to protect the sacred drum, as well as to play and sing during the balché ritual, involving the sacred beverage made from the bark of the tree of the same name and used in therapeutic and propitiatory ceremonies.