No wonder primates have become a reference point for our understanding of what is human. What a tragedy it is, I reflected, that we seem to be driving some of them to the edge of extinction. Seen from the window of the 20-seater plane on the first leg home, the rainforest parted occasionally for the elegant snake of a river or the livid orange slash of a forestry road. I thought of Pete down there somewhere, educating her offspring and teasing the odd passing human. In a decade's time, when I am 45 and she is 20, I shall wonder whether she lives there still.
Volunteers help monitor orang-utans in the rainforest and do laboratory and computer work.
A 14-night trip costs pounds 1,260 and includes food and simple shared accommodation just outside the national park, but excludes flights. Several adventure tour operators run trips to Tanjung Puting. Prices range from pounds 350 to pounds 720, excluding international and internal flights. The area is easily accessible and busy with the local and foreign tourist trade. But it is remoter and much quieter.