Homo sapiens may not be well adapted to living in trees – we lack tails and opposable toes – and there is no fossil evidence to suggest that we ever did. However, tree-dwelling is common in certain remote tribal jungles, and in basin of the Brazza River in west Papua, Indonesia, the Korowai people build the tallest tree-houses of all. Using only the natural resources to hand, the Korowai can erect sturdy habitations high off the ground on stilts or, higher still, in the tips of trees, sometimes at a height of 30 m (100 ft). There have even been accounts of tree-building as high as 50 m (165 ft) during times of conflict, despite the tribe’s use of stone-age tools such as bone- or stone axes.

A story from The New York Times dated 7 September 1903 recounts a despatch in the (now-defunct) Daily Chronicle newspaper about the recent discovery of an “extraordinary tribe of marshland dwellers… gradually losing the use of their lower limbs and are unable to walk on hard ground without their feet bleeding. Their bodies developed enormously, while their legs and thighs have become atrophied. In figure and carriage the natives are apelike.” However, recent ventures into the Korowai’s territory have dispelled this idea that the arboreal life leads to a withering of the lower limbs! The Korowai current number around 3,000.