"The deer dance of the Yaqui, (Yoeme) people of Sonora is sacred and rarely photographed. The deer represents good and tells the story of the deer, his brother and the Seyewailo, flower world. It is said to have been held before a deer hunt, thanking the deer for his sacrifice so that the people may live.
Deer dancers, pahkolam, "old men of the fiesta" wear rattles around their ankles made from butterfly cocoons, honoring the insect world, and rattles from the hooves of deer around their waist, honoring the many deer who have died.
Instruments include the water drum (the deer's heartbeat) an animal skin frame drum, rasp (the deer's breathing), gourd rattles held by the dancers (honoring the plant world), as well as the flute, fiddle, and frame harp, of Spanish influence."
This information, as well as a good, informative video was found here: