The cantaro is a percussion instrument. It is a clay pot that is struck in its outer surface or mouth with a hand, creating different effects. Water can be used to pitch the instrument to a desired sound.
In Mexico, particularly in the states of Guerrero and Oaxaca, it is used to accompany chilenas, sones, parabienes, gustos, minuetes, jarabes oaxaqueños, and danzas indígenas. The cantaro is also used in the fandangos mixtecos of Puebla.
References
Cantaro Wikipedia(Text) CC BY-SA