"What do we mean when we speak of Native American religion? Unlike Buddhism, Christianity, and Islam, it has no single founder. Unlike Judaism, it is not the ongoing story of a people with a strong sense of their own identity. Neither does it resemble Hinduism, with its ancient and all-inclusive adaptiveness. In a sense, Native American religion does not exist at all: There is no one religious expression common to the 250 distinct Native American peoples still surviving as America approaches the 21st century. And complicating the question even further is the fact that few Native American people today can say for sure how their ancestors worshipped before the onslaught of European immigrations: Too much death lies between the present and pre-Columbian America, too much cultural devastation, too many forced conversions to Christianity. The chain of elders preserving tradition was broken by disease and war. Many contemporary Native Americans interested in knowing their own heritage have found themselves in the peculiar position of needing to consult anthropologists for information."

From: Native American Religion: http://www.stormwind.com/common/nareligion.html