Hainan, with its varying climatic zones, is home to a huge diversity of wildlife predominantly found in the rain forests. The Hainan moonrat (Neohylomys hainanensis) and Hainan flying squirrel (Hylopetes electilis) are indigenous to Hainan. These creatures are small members of the hedgehog family although they bear more of a resemblance to large rats and frequently search for prey in water. They feed on a range of crustaceans, molluscs and fish although most species will also feed on fruit and berries.
One Hainan species features on the IUCN Red List of critically endangered species is the Hainan Black Crested Gibbon (Nomascus hainanus). The primate is a subspecies of the Eastern Black Crested Gibbon found on Hainan Island and in the Hoa Binh and Cao Bang provinces of Vietnam. Its habitats consists of broad-leaved forests and semi-deciduous monsoon forest. Living in small family groups with a monogamous male, a female and their offspring, young are usually born every two to three years. Unlike many other primates, the females lead groups of this gibbon. It feeds on ripened fruit, leaves and insects. The major threat to the animal is deforestation due to land clearance for agriculture which explains the dramatic drop in the gibbon population over the last century.
As of October 2007 there were only 17 reported individuals remaining in Hainan.
Many spider species are also to be found on the island with some specimens reaching an overall length of more than 10cm. In the last ten years, more than six new species of spider and have been discovered in the rainforests of Hainan.
Other mammal species found on the island include the Thamin or Hainan (Eld) deer (Cervus eldi hainanus), the Asiatic black bear (Selenarctos thibetanus) and the Hainan mole (Talpa insularis).
With regard to bird species, both the Hainan leaf warbler (Phylloscopus hainanus) pictured above, and the Hainan partridge (Aborophila ardens) are listed as endangered. The Hainan partridge (below), is now a restricted-range bird species along with the ratchet-tailed treepie (Temnurus temnurus) and white-eared night heron (Gorsachius magnificus). The latter species has not been sighted for more than 30 years and may be extinct.
According to birdlife International, there are about 46 subspecies of birds indigenous to Hainan, several of which may be regarded as full species. Two other threatened bird species occur on Hainan but these have a wider range, they are the pale-capped pigeon (Columba punicea) and the Blyth kingfisher (Alcedo hercules), both of which are considered vulnerable.
Of the invertebrates, the Hainan torrent frog (Amolops hainanensis) also known as the Hainan sucker frog, is a heavily camouflaged green and yellow species that is considered endangered by the IUCN. The frog grows up to 80mm in length and lives on rocks near high velocity rivers or waterfalls.