The lar gibbon (Hylobates lar) of Thailand is one of the most vocal non-human primates that exist. Esther Clarke and colleagues are the first to decipher the subtle and soft “hoo” utterances of lar gibbons and have found the communications to be close to a language.
Scientists have known that lar gibbons have two forms of communication since 1940. The loud vocalizations are easily discernible from the soft utterances that are called hoos. The soft utterances have been found to function as a primal language in lar gibbons.
The researchers followed groups of lar gibbons around the forests of Thailand for four months recording the soft language of the animals. The scientist found that gibbons regularly use 450 different combinations of hoo sounds for different purposes. Some hoos indicate a particular type of predator, some are considered to be an announcement that a mated pair occupies a given territory, and some have yet to be decoded. The gibbons made the same sounds with live predators and fake predators placed in their territory by the researchers.
Lar gibbons have different sound that indicates a predator is a cat like a leopard or a tiger, a bird like an owl or eagle, and a snake. The sound for tiger and leopard is the same and is thought to indicate the word cat in human language. Female gibbons have a lower voice tone than males. Males usually have a lower register of vocalization in most species of animals.
The researchers indicate that this discovery may be one of the first clues to the origins of communication in people. Gibbons are one of the most genetically similar primates to man. No research has ever shown such a similarity in non-human vocalizations to a language before.
