Any member of any of several closely related ethnic groups of central Sumatra, Indon.
The Batak are descendants of a powerful Proto-Malayan people who until 1825 lived in relative isolation in the highlands surrounding Lake Toba in Sumatra. They have their own written language. In their traditional religion, ancestors, plants, animals, and inanimate objects are considered to possess souls or spirits; today about a third of the 3.1 million Batak adhere to traditional beliefs, while the rest profess Christianity or Islam.