Abstract In a small national park in the Jambi province of Sumatra, Indonesia lives Orang Rimba. A group of matrilineal, animist, hunter-gather and occasional swidden cultivating forest dwellers. They call themselves, Orang Rimba, which translates to People of the Jungle , indicating their dependency and their connectedness with the forest. Over the past decades the Sumatran rainforest have diminished drastically. The homes of thousands of forest dwellers have been devastated and replaced by monoculture oil palm plantations that push Orang Rimba away from their customary land. Development projects, national and international governments, the Non-Governmental Organisation KKI Warsi through initiatives such as Reducing Emissions from Deforestation and forest Degradation (REDD) seek to conserve forests and develop peoples . In the middle of all this Orang Rimba are struggling to keep their eminence as a group who define themselves in contrast to others , people of the outside . The core question this thesis asks is how physical changes in the environment have affected Orang Rimba of Bukit Duabelas and their perceptions of the world. It answers the question by going through Orang Rimba now and then , drawing mainly on the works of Steven Sager (2008) and Øyvind Sandbukt (1984, 1988, 2000 and in conversation) as well as other comparable literature to compare. It proves that Orang Rimba have moved from being a group almost completely isolated from the world outside the forest to a group in nearly daily contact with the outside dependent on foods, trading partners and the monetary economy represented by the outside. Their significant adat customary system however, reveals that women play a significant role in Orang Rimba s success not to assimilate into major society. Simultaneously, their traditional practices are daily challenged by outside influences. This thesis goes through the changes and challenges, and adjustments Orang Rimba face in a world that is physically changing through deforestation, and socially changing through increased interaction with others . It concludes that despite changes, Orang Rimba have managed to keep their sense of belonging in the forest, where the majority have interest in keeping it intact.