'Big Island' in the Mende language, 12-sq-km Tiwai Island certainly packs a punch when it comes to its primate population. Set on the Moa River, the entire island is run as a conservation research project. There are over 700 different plant species, 11 species of primates – including Diana monkeys and chimpanzees – 135 bird species plus otters, sea turtles and the endangered, elusive pygmy hippopotamus.
From Bo or Kenema, the departure point for Tiwai is Poturu; from Freetown, head to Kambama (eight hours). Speedboats (US$10 per person including island entrance fee) carry you the short distance to the island, where you can overnight on canopied platforms (US$20 per person) and drift off to sleep, listening to the midnight chatter of the rainforest.
Guided forest walks cost between US$4 and US$6 per person, depending on the size of the group. Canoe tours cost US$10 per person.