For this group of people their major technological advantage was sea travel -- and due to this, other peoples could not actually compete with them. They were the first and only settlers to these islands for quite a while. Shockingly, Africans never colonized Madagascar until relatively recently in history. "There is archaeological evidence that Bantu peoples, agro-pastoralists from East Africa, may have begun migrating to the island as early as the 6th and 7th centuries." https://en.wikipedia.org/wiki/History_of_Madagascar