Chimpanzees live in big groups called 'communities' of around 20 to 150 members. The group splits up into smaller travelling parties during the day and comes back together to sleep at night. Each chimp builds its own nest of leaves and branches in a tree, fresh every evening - they don't reuse the same nest.
Chimps are famously clever. They use sticks to fish termites out of nests, stones to crack open hard nuts, and chewed leaves like sponges to soak up water from holes in trees. Different communities have different traditions - the chimps of Nyungwe may use slightly different tools than chimps in Tanzania, just like different schools have different playground games.
They talk to each other with a mix of sounds. A loud 'pant-hoot' call can travel for over a kilometre through the forest. It is how chimps tell each other where they are. They also hug, kiss, hold hands, tickle and pull funny faces - very recognisable behaviour to anyone who has been a child in a school playground.
Visitors to Nyungwe can sometimes follow a guide quietly through the forest at dawn, listening for the chimps waking up in the trees overhead. The first sound is usually one chimp pant-hooting to another, then a chorus across the canopy. It is one of the most magical sounds in any African rainforest.