Two adult Hainan gibbons, or Nomascus Hainanus, move on a tree in a nature reserve in Bawangling of south China's Hainan Province, Sept. 11, 2015. The Hainan gibbon is one of the least in number of all current primates and they live only in wild tropical rainforests in Hainan Province. According to observation, less than 25 Hainan gibbons live in the Bawangling nature reserve. (Xinhua/Yang Guanyu)