Hoolock gibbons are 'apes', not 'monkeys' - which means they don't have a tail. To swing through trees, they don't need one. Their arms are about twice as long as their legs. With one strong arm, they can grab a branch and fling themselves up to ten metres across to the next one.
They live in small family groups - a mum, a dad and one or two children. Each family has its own patch of forest, and every morning the parents sing a long duet together to tell other families 'this forest is ours'. The song goes on for ten or fifteen minutes and can be heard from over a kilometre away. Whole forests wake up to it.
Adult male hoolock gibbons are black with white eyebrows that look like fluffy white moustaches above the eyes. Adult females and babies are pale gold. When a baby is born, it is the same colour as its mum - then the boys slowly turn black as they grow up. From a distance, you can guess a gibbon's age and gender just from its colour.
Hoolock gibbons rarely come down to the ground - they spend almost their whole lives in the trees, eating fruit, leaves and the occasional insect. Northern Myanmar's forests have some of the last good homes for them in the world. Communities and scientists work together to protect the trees the gibbons need.