Produced in German, this series contains 20 lessons on the intermediate level for teachers to use in foreign language science study. The largest species of the gibbon family in the forests of Sumatra and Malaysia is the siamang. The siamangs are excellent swingers due to their arm spread of 5 feet. According to this segment, these animals live in monogamous family groups, and the male and female are bonded for life. Siamangs are also known for their duet song that is used to mark their territory.