Most commonly in Survivor, the tribes are divided by the moderators before the game begins.
Returnees vs. Newbies
Some seasons have had the contestants split between those who had played in a previous season, and those who hadn't.
Survivor: Cuba was the first season to implement this, pitting ten veterans from the previous two seasons and ten new players against one another. Unlike the other returnee vs. newbie seasons, the returnee tribe did not have an archetype.
Survivor: Madagascar and Survivor: Rome were both Fans vs. Favorites themed. One tribe consists of new players, dubbed the Fans, while the other consists of memorable previous contestants, dubbed the Favorites.
In a controversial twist, however, Madagascar split both fans and favorites evenly between both tribes.
Anarchy
Used by both Survivor: Anarchy and Survivor: Alsace-Lorraine, Anarchy is a game-changing twist in which for the first stage of the game, no tribes are established. More often than not, the highest placing half will win immunity for a cycle while the lowest placing half will be vulnerable. Tribes are introduced later in the game.
