'Chaac' (also rendered as 'Chaak' or 'Chac') is the originally
Yucatec name of the
Maya rain deity. With his lightning axe, Chaac strikes the clouds and produces thunder.
Rain Deities and Rain Makers
Like other Maya gods, Chaac is both one and manifold. Four Chaacs are based in the cardinal directions and wear the directional colours. Contemporary Yucatec Maya farmers distinguish many more aspects of the rain and the clouds and personify them as different, hierarchically-ordered rain deities. Especially the Chorti Mayas have preserved important folklore regarding the process of rain-making, which involved rain deities striking rain-carrying snakes with their axes.
The rain deities had their human counterparts. In the traditional Mayan (and Mesoamerican) community, one of the most important functions was that of rain-maker, which presupposed an intimate acquaintance with (and thus, initiation by) the rain deities, their places, and their movements. The well-known Mesoamerican tale of the 'sorcerer's apprentice' playing for rain deity belongs in this context.
Images of the Great Water Cycle
Particularly the
Huaxtec Mayas have a cyclical concept of the water. Virile, young lightning deities dominating the skies during the rainy season are being transformed into wasted, subterranean old men (Mamlab) during the dry season; in the ocean, the old men rejuvenate themselves again. This concept is likely to have existed among the Classic period Mayas as well.
Rituals
Among the rituals for the rain deities, the Yucatec Cha-Chaac ceremony for asking rain was a ceremonial banquet for the rain deities; it included four boys acting as frogs. Asking for rain and crops was also the purpose of the 16th-century rituals at the karstic wells, or
cenotes, of Yucatan. Young men and women were lowered into these wells and left to drown there, so as to make them enter the realm (and possibly, the escort) of the rain deities. Alternatively, they were thrown into the wells later to be drawn up again, and give oracles.
Mythology
The rain deity is a patron of agriculture. The main myth in which the Chaacs (or related Rain and Lightning deities) have an important role to play is about the opening of the mountain in which the maize was hidden. In
Tzotzil mythology, the rain deity also figures as the father of nubile women representing maize and vegetables. In some versions of the
Q'eqchi' myth of Sun and Moon, the rain deity Choc (or Chocl) 'Cloud' is the brother of Sun; together they defeat their aged adoptive mother and her lover. Later, Chocl commits adultery with his brother's wife and is duely punished; his tears of regret give origin to the rain.
Iconography
Chaac is usually depicted with a human body showing reptilian or amphibian scales, and with a non-human head evincing fangs and a long, leafy nose. He often carries shield and lightning-axe, the axe being personified by a closely related deity, called
Bolon Dzacab in Yucatec.

ChacDresden.jpg
A large part of the most important Maya book, the
Dresden Codex, is dedicated to the Chaacs, their locations, and activities. It illustrates the intimate relationship existing between the Chaacs, the
Bacabs, and the aged goddess,
Ixchel. The main source on the 16th-century Yucatec Mayas, Bishop de
Landa, combines the four Chaacs with the four
Bacabs and Pauahtuns into one concept. The Bacabs were aged deities governing the subterranean sphere and its water supplies, corresponding to the Huaxtec Mamlab mentioned above.
In the Classic period, the king often impersonated the rain deity (or the associated rain serpent) while the pictogram of the rain deity may accompany the king's other names. This may have been related to the king's role as a war chief, metaphorically equated with the violence of a thunderstorm. It may also, however, have given expression to his role as a supreme rain-maker.
About Chaac's role in Classic period mythological narrative, little is known. However, he is present at the resurrection of the
Maya maize god from the carapace of a turtle representing the earth. Together with the skeletal Death God, he also seems to preside over an initiate's ritual transformation into a jaguar.
References
★ Cruz Torres, Mario, ''Rubelpec''.
★ Redfield, Robert, and Alfonso Barrera Vasquez, '' Chan Kom''.
★ Taube, Karl, ''An Illustrated Dictionary of the Gods and Symbols of Ancient Mexico and the Maya''.
★ Tozzer,Alfred, ''Landa's Relación de las Cosas de Yucatán, a Translation''.
★ Wisdom, Charles, ''The Chorti Mayas''.