Tribal tattoos have been practiced for thousands of years. Modern people still get them done for many reasons such as to belong to a modern 'tribe' even if they do it on a subconcious level.
Getting tattooed was also seen as a rite of passage into adulthood. A belief goes that if a girl can't take the pain of tattooing, she is un-marriageable, because she will never be able to deal with the pain of child birth. If a boy can't deal with the pain he is considered to be a bad risk as a warrior, and could become isolated from the tribe.
Some primitive tribes use tattooing as a rite of social status. The Maori, of New Zealand use tattooing primarily for this purpose. To the Maori, a person's Moko designs enhanced their prestige and show transition from one social status to another. At its highest level, Moko designs proclaimed the sacredness of chieftanship.
The Hawaiians are prominent among people who have specific tattoo gods. In Hawaii, the images of the tattoo gods are kept in the temples of tattoo priests. Each tattoo session begins with a prayer to the tattoo gods that the operation might not cause death, that the wounds might heal soon, and that the designs might be handsome. Many modern American tattooist will tell you, "When you should get a tattoo, the tattoo god will tell you that it is time."
In the 1970's, American tattooing discovered primitive, tribal tattoos. People wanted simple designs with meaning and they began copying designs, primarily from the islands of the South Pacific. In the past few decades, people of European stock began looking for tribal tattoos of their own origins and created a new form of tattoo commonly known as neo tribal tattoos.