Yellow-cheeked Gibbon

The yellow-cheeked gibbon, scientifically Nomascus gabriellae and named after the British naturalist Gabrielle Maud Vassal, is native to Vietnam, Laos and Cambodia, where it inhabits primary tropical forest. All individuals are born blond and later turn black; adult males stay black with distinguishing golden cheeks, while females turn back to blond at sexual maturity, keeping only a black cap on the head. It is diurnal and arboreal, foraging for fruit and moving through the trees by brachiation, and has a lifespan of approximately 46 years. Gibbon groups vocalize loudly in the early morning, and mated pairs duet with a coordinated song containing sex-specific phrases. It is listed as Endangered on the IUCN Red List and included in CITES Appendix I.