Hylobatids (gibbons and siamangs) are the smallest of the apes distinguished by their coordinated duets, territorial songs, arm-swinging locomotion, and small family group sizes. Although they are the most speciose of the apes boasting twenty species living in eleven countries, ninety-five percent are critically endangered or endangered according to the IUCN's Red List of Threatened Species. Despite this, gibbons are often referred to as being 'forgotten'...