The term 'Sumatran Simian' refers to two species of primates native to the Indonesian island of Sumatra: the ORANG (5 letters) and the ORANGUTAN (9 letters). Both species are endangered due to deforestation and poaching, and are considered to be among the most intelligent of all primates. The ORANG is a species of great ape, while the ORANGUTAN is a species of lesser ape. Both species are known for their reddish-brown fur and long arms.