Gibbon, for one, is an APE that belongs to the lesser APE family. It is a small, tailless primate with long arms and legs, and is found in tropical and subtropical forests of Southeast Asia. Gibbons are known for their loud calls and acrobatic abilities, and are the fastest and most agile of all tree-dwelling, non-flying mammals. They are also highly intelligent and social animals, living in family groups consisting of a mated pair and their offspring.