Sakai is a minority group with dark skin and curly hair, residing in the forests of the Malay Peninsula including in provinces in the lower southern region of Thailand. Ethnically, the group is categorized as Nigrito, a Negroid sub-branch. Linguistically, it is in the Austroasiatic Family, Mon-Khmer Sub-Family. Anthropologically, the group is divided into Semang, Sakai and Senoi. The Sakai have dark skin and are approximately 145-155 centimeters in height. They live a nomadic life as hunters and gatherers. They are animists, believing that sickness is caused by spirits. In the past, the Sakai in Trang Province were divided into five groups, namely Upper Khlong Tong, Khlong Hin Daeng, Chao Pha, Nai Singha and Nang Yam. The latter two groups later moved to Manang Village of Satun Province. Socially, the three groups in Trang Province lead a monogamous life. They are related by family lineage. Group formation normally consists of at least two families with 15 to 30 members. An elderly person called Thap or Hahya is the leader of the group. The shelters of the group are built facing one another in almost a circle. However, the formation of the Chao Pha Group is different, consisting of families of siblings. Group members can marry one another but not those with the same parents.