Recently, I had an encounter with one of the world's most charismatic creatures.
Deep in the primary rainforest of Malaysian Borneo, I came face to face with a "man of the forest", as the name orang-utan means in the local language.
My encounter was in the state of Sarawak, at the Matang Wildlife Centre.
Animals uprooted by deforestation or poaching are rehabilitated, then returned to the wild in the surrounding Kubah National Park.
It was there that I helped volunteers stuff hessian sacks with tapioca, jam, nuts and sunflower seeds. Wearing a surgical mask and gloves (orang-utans are susceptible to human diseases), I handed Aman, a 25-year-old male orang-utan, one of the sacks. He carefully shucked each sunflower seed, extracting the contents with his tongue.
Aman regained his sight after a pioneering operation on his cataracts. He is too old to be returned to the wild, but the younger orphans can be taught how to survive on their own.
This includes lessons in the rainforest, and I joined four young orang-utans and six rangers one afternoon.
It was like being with toddlers. The orang-utans had tantrums and lay down, refusing to move. Except for the ginger hair and wrinkled faces, it could have been my son out there. Without parents, these youngsters rely on rangers to teach them to forage and climb. One, terrified of heights, overcame vertigo after watching its foster carer climb a tree.
Soon the youngsters tired and it was moving to see them riding piggyback or holding their human carers' hands as they wandered back, clutching fruit and sticks they had collected during the afternoon.
Orang-utans are not the only primates in Sarawak. In Bako National Park, I encountered one of the rarest, the proboscis monkey. They are famous for unusually large noses and, as a large-nosed individual, I felt a kindred sense of pride.
Bako National Park is accessible only by boat; then we trekked again in almost 100 per cent humidity. Sweat streamed down my face and leeches were poised to hitchhike on stray legs, especially those with the sweet pale skin and blood of an Englishman.
You may need to work hard, but it pays off - especially when you meet a "man of the forest".