In the beginning of the game the eighteen contestants are split into either two or three tribes. When the game was being created the teams were random, but in the past few years the tribes have been based of some aspect of the people on it. The recent themes have been: Blood vs. Water, Brain vs. Brawn vs. Beauty, and White Collar vs. No Collar vs. Blue Collar. These tribes compete in challenges, and the losing tribe has to go to Tribal Council and vote one of their own tribe members off. Each of the tribes has to live with each other for weeks. They have to make their own shelters out of what they can find on the island and sleep there. Food is obviously very important and each tribe is given a big bag of rice and bean. The rest they have to either win in reward challenges or find on the island. Dysfunction on a tribe is common and this leads to poor performance in challenges and a bad tribe. Collaboration is key.two tribes