Wikipedia
The Antambahoaka are the least numerous ethnic group in Madagascar, numbering around 50,000 in 2013. They inhabit a small region along the southeastern coast of Madagascar near Mananjary and share their origins with the partially Arab Antaimoro people, from whom the group split in the 15th century under a leader named Ravalarivo. Very little is known about the history of this group after its founding. The Antambahoaka speak a dialect of the Malagasy language, which is a branch of the Malayo-Polynesian language group derived from the Barito languages, spoken in southern Borneo.
The Antambahoaka are widely known for their Sambatra festival, a ritual group circumcision ceremony that occurs every seven years. This festival has been the focus of two short films released in 2008 and 2010. Their society is highly homogenous with little external migration and a strong sense of unified identity. Patriarchy, ancestor veneration and adherence to ancestral taboos ( fady) are core elements of their social structure. There is a long-standing taboo against raising twins that historically led them to be killed immediately after birth or left to die of exposure in the forest. Human rights groups and the Malagasy government are working to provide support for twins and their parents in the effort to put an end to this tradition.