The current population of Siberut is roughly 25.000. The population is mainly of Mentawaian origin, with a substantial number of Minang immigrants who have settled on Siberut, especially on Muara Siberut and Muara Sikabaluan. Most Mentawaian have traditional settled inland along the banks in the upper reaches of rivers. The major source of carbohydrate is sago palm (Metroxylon sagu), which grows in natural swamps. Fish, prawns and pig are the most common sources of protein.