Survivor: Panama — Exile Island, also known as Survivor: Panama, is the twelfth season of the American CBS competitive reality television series Survivor. The game began with the 16 competitors split into four tribes by both relative age and gender. They were introduced to the concept of "Exile Island" with the promise of a hidden immunity idol located somewhere on it, while one person from the losing tribe at challenges would be sent to the island and given clues to look for it. After the first four days, the four tribes were merged by schoolyard pick with mixed genders into two tribes, Casaya and La Mina. Each week at least one castaway is banished to Exile island away from all other contestants for the time period between the reward and immunity challenges. The castaway is given a single machete, a flint, a pot and a bucket of non-sanitized water.