If you are examining the religious beliefs of Native Americans (the US term) or the First Nations (Canadian usage), the first thing you need to take into account is that there are many different tribes, each with complex and fully developed sets of beliefs and ceremonies, comprising several thousand years of oral and artistic traditions.
One general characteristic is that, as is the case with most oral cultures, the religious and spiritual traditions of most tribes are grounded in ritual and ceremony rather than abstract theology. Rather than there being some fixed written "scripture" or one unique sacred text, their belief systems are expressed in numerous stories or poems, often publicly recited during specific ceremonial occasions. Often artwork or physical objects (especially sand painting among the Navajo), costume, song, and dance are as integral to the religions as text. Sacred places are also an essential part of the religious heritage.
In general, Native American religions are close to the natural world, and grounded in explaining and understanding natural phenomena. They tend to be polytheistic, including a belief in many gods or spirits, usually linked with specific aspects of the natural or human world. The goal of most religious ceremonies is both to obtain the favor of these being and to reconcile people with them. Shamans or medicine men are often the repositories of knowledge about the gods or spirits and generally lead religious ceremonies.
Although many indigenous people were converted to Christianity (sometimes forcibly) during the period in which Europeans settled the Americas, most tribes have worked to revive their native beliefs and traditions over the twentieth century.
What are the principal reasons for the proportional decline protesting dominions in contemporary America