Nomascus hainanus, commonly known as Hainan black-crested gibbon, is a primate endemic to Hainan Island and a national first-class protected animal. This rare mammal also indicates the integrity and authenticity of the Hainan rainforest ecosystem. It is only found in the BaWang Ling area of Hainan Tropical Rainforest National Park. At the 19th Congress of the International Primatological Society in 2002, Nomascus hainanus was identified as the most critically endangered primate in the world.

Protection class

It is a Class I national protected animal. It is also listed as Critically Endangered (CR) on the IUCN Red List of Threatened Species.

Morphological characteristics: Hainan black-crested gibbons look like monkeys but have no tail. They can live up to 40 years on average and adults weigh about 10 kg. Usually 5-10 gibbons live in a social group. This species generally reaches sexual maturity 8 years after birth. A female gibbon often gives birth to one baby each time every two years after a gestation period of 7-8 months. Hainan black-crested gibbons are born with golden brown hair, which turns black after 6 months or so and tells the difference between males and females as the gibbons become sexually mature. An adult male gibbon is black while the female is golden in hair.

Habits: The acoustic structure of Hainan black-crested gibbons is different from that of other apes. The first cry every morning is made loud enough to mark their territories, and that is how researchers monitor the population size of this species. Each gibbon group occupies a home range of 2 square kilometers. The most common food sources for Hainan black-crested gibbons are the fruits and young leaves from more than 130 plants such as Litchi canensis, Ficus auriculata Lour., Clusiaceae, Skeels, Blume, Castanopsis, and Bischofia javanica. Juicy fruits make the best choice for them, but sometimes they feed on bird eggs too. As a kind of arboreal animal, the Hainan black-crested gibbon species move around or seek food in forest canopy.

Conservation status: In an attempt to protect Hainan black-crested gibbons, a provincial-level nature reserve in BaWang Ling area was approved for establishment by the People’s Government of Guangdong Province in 1980, when there were only 7-9 gibbons living in two groups. In 1988, the reserve was promoted to a state-level nature reserve with the approval of the State Council. Strict conservation efforts and habitat restoration have contributed to the steady increase in the population of Hainan black-crested gibbons. Today, 37 individuals are living in six social groups in the reserve.