The siamang (Symphalangus syndactylus). Siamangs are close and bigger cousins of gibbons. Some of their characteristics are more athletic body shape and louder calls. In the same way as the gibbons, males and females join in monogamous relationships for lifetime. Groups consist of two adults and offspring that remain with them until they are 7-8 years old. They prefer to live in the lowland forest but because lowland forests are gone, they make living in the mountainous terrain.