Collectively, their organizations are called "tribes". Many of the tribes also parade on the Sunday nearest to Saint Joseph's Day on March 19 ("Super Sunday") and sometimes at the annual New Orleans Jazz & Heritage Festival.
There are about 38 tribes. They range in size from a half dozen to several dozen members. The tribes are largely independent, but a pair of umbrella organizations loosely coordinate the Uptown Indians and the Downtown Indians.
Mardi Gras Indians have been parading in New Orleans at least since the mid-19th century, possibly before. The tradition was said to have originated from an affinity between Africans and Indians as minorities within the dominant culture, and blacks' circumventing some of the worst racial segregation laws by representing themselves as Indians. There is also the story that the tradition began as an African American tribute to American Indians who helped runaway slaves. These slaves married into the tribes on occasion. An appearance in town of Buffalo Bill's Wild West Show in the 1880s was said to have drawn considerable attention and increased the interest in masking as Indians for Mardi Gras.
When Caribbean communities started to spring up in New Orleans, their culture was incorporated into the suits, dances and music made by the "Indians".
In the late 19th century and early years of the 20th century, the tribes had a reputation for violent fights with each other. This part of Mardi Gras Indian history is immortalized in James Sugar Boy Crawford's "Jock O Mo" (better known and often covered as "Iko Iko"), based on their taunting chants.
As the 20th century progressed, physical confrontation gave way to assertions of status by having better suits, songs, and dances. Generations ago when Mardi Gras Indians came through neighborhoods, people used to run away; now people run toward them for the colorful spectacle.
A tradition of male-only tribes ended in the late 20th-century as women began appearing in costume as well.
Generally each "Indian" makes his own suit, assisted by family and friends to sew elaborate bead and feather work —A chief's suit can weigh up to 150 pounds (68 kg) and cost up to U.S. $5,000 — and traditionally a new suit is required each year. Beads and materials were once reused from one year's suit on the next.
On St. Joseph's night the Indians would come out and parade their suits one last time before taking them apart and burning anything they didn't reuse. In recent years, however, there has been a market for selling suits after they are worn for display by museums and private collectors.
The Mardi Gras Indians play various traditional roles. These include the "chief", the "spy boy" who goes out in front of the group, the "flag boy" who bears the tribe's standard and uses it to communicate between the chief and the spy boy, and the "medicine man".
Long-time Mardi Gras Indian "Chief of Chiefs" Tootie Montana on Indian hierarchy:
"You've got first chief, which is Big Chief; First Queen; you've got Second Chief and Second Queen; Third Chief and Third Queen. First, Second, and Third chiefs are supposed to have a queen with them. That's just tradition. I found them doing that. Your fourth chief is not called fourth chief, he's the Trail Chief. From there on it's just Indians, no title. You also have your Spy Boy, your Flag Boy and your Wild Man. Your Spy Boy is way out front, three blocks in front the chief. The Flag Boy is one block in front so he can see the Spy Boy up ahead and he can wave his flag to let the chief know what is going on. Today, they don't do like they used to. Today you're not going to see any Spy Boy with a pair of binoculars around his neck and a small crown so he can run. Today a Spy Boy looks like a chief and somebody carrying a big old stick. It's been years since I seen a proper flag. Today everybody has a chief stick. The Wild Man wearing the horns in there to keep the crowd open and to keep it clear. He's between the Flag Boy and the Chief."