protecting this unique environment has become peter pratje's life's work. >> of the orangutans still6000 living in the wild here on sumatra, only 1600 live in protected areas. the future will depend on how well these sanctuaries are protected. that will prove decisive in determining whether the species is still around in the next millennium or whether it will die out. >> near the reintroduction station there are signs of logging and slash-and-burn land clearing. palm oil plantations, in particular, keep encroaching on woodland. some 2/3 of sumatra's rainforest has vanished over the last 50 years -- taking the orangutans' habitat along with it. so preserving the rainforest is now conservationists' top priority. back at the jungle camp, a new orangutan has arrived. around 10 come here for training each year. >> we have a new orangutan. his name is ugo blanco and he was kept illegally. he's just 5 years old and needs training so that eventually he can survive on his own in the forest. >> dora's days of living in a cage are over. her trainers have decided that she's ready to be released