Tribes are competing teams in the 703 Survivor seasons. Tribes usually have between four to eleven people at the beginning of the game; the largest tribe was Tarachi, which had 16 people at its peak, while the smallest are the tribes of Survivor: Chaos, which originally had 2 players.
Most commonly in Survivor, the tribes are divided by the moderators before the game begins.
In Survivor: Wales, the castaways were initially not assigned into a tribe. There was a Day 1 Challenge, in which the highest scoring female and highest scoring male would be responsible for starting the Schoolyard Pick.