Jim White talks to Birute Galdikas about her work to save the orang-utan, an animal the public knows mainly as a co-star in Clint Eastwood movies
Last Monday it was bucketing down in London with an intensity that must have been familiar to anyone who had spent the past 23 years in the tropical rain forests. But you could sense that Birute Galdikas was not comfortable. And, though not naturally inclined to self-promotion, it was not being interviewed that made her ill-disposed. It was simply that she does not like to spend too long out of the Borneo forest where she lives and works and looks after her family. She fears that if she does, it might not be there when she gets back.

"This is serious," she says. "A friend was undertaking field research in another part of the forest in Borneo and went back to north America to do some lecturing. They returned six months later to discover that their study area had turned into suburbs."

Anyone who tried to open a fast-food franchise, build an executive cul- de-sac or develop a shopping mall where Dr Galdikas's bit of forest is, would, however, encounter a fearsome opponent. This is not a woman to cross. She will not fear a few chainsaws or worry about a couple of bulldozers, for she has engaged, for nearly a quarter of a century, with the following in the course of an ordinary working day: leeches, bloated with blood, tumbling out of her socks and underwear when she gets undressed; red ticks, looking like chilli powder sprinkled on the skin, which bore their heads into soft, unprotected flesh; fire ants invading hammocks at night in their thousands, making the occupant "bolt like a horse from a burning stable"; and, worst of all, mosquitoes, with their constant irritating whine.

"There is always one with you," she says. "I've never gotten used to that. Or to the humidity, like someone's tipped a pot of glue over you."

Besides, Dr Galdikas isn't going to defer to any bulldozer when she has her family to protect. More than 60 individuals, orphans and the elderly, depend directly on her. And for another 30,000 in imminent danger around her in South-east Asia, she represents almost a last hope. They are her orang-utans.

"We often ask what man's closest relative is. Well, let's turn this around and ask what the orang-utan's closest relative is," she says. "It's man. A doctor I work with told me that orangs and man may look different from the outside, but cut us open and we look exactly the same. As an experiment we once sent some orang blood to a hospital as human blood for testing. They never noticed. We owe it to orangs to see that they survive. This is family."

Give or take a few dozen snatched from the wild to serve as pets for the rich of Taiwan, the orang-utan is not being poached into extinction. The ape is disappearing because it lives in Asian tropical rain forests, a part of the world that is being destroyed with a speed that makes the destruction of Britain's countryside look restrained. The woman who stands in the way of its total destruction is Birute Galdikas.

"The part of the forest where I work will last as long as I'm there. The locals have told me that the moment I've gone they want that wood and will have it before anyone else gets it."

The Tanjung Puting National Park, where Dr Galdikas is based, is under such pressure that to arrive there looks like happening upon Kew Gardens. You drive down a tarmaced road, lined with houses and shops, and then suddenly the trees rear up in front of you. Primary tropical rain forest has turned into the green belt.

It was somewhat different in the early Seventies, when the conservationist Louis Leakey sent three women out into the wilds to study the great apes. Dian Fossey he dispatched to get to know the gorillas, Jane Goodall to discover chimpanzees, and Birute Galdikas went to Borneo to learn about orang-utans. Leakey chose women, he said, because they were more observant than men.

"He reckoned we pick up on the irrelevant details more," Dr Galdikas says. "And in research any detail which seems irrelevant can be most relevant later on."

The irrelevant detail this softly-spoken Canadian of Lith-uanian extraction discovered two months after arriving in Borneo was that orang-utans were to exercise a total grip on her consciousness. Encountering her first wild ape, as it careered across the forest canopy sending branches crashing on her head,was a spiritual experience.

"There is something in their eyes," she explains. "Unlike the other great apes, the iris of their eyes is surrounded by white. Look into an orang's eyes and the gaze reflects your own. They come right up to you in the wild and look into your eyes as if they are searching into your soul. The strongest supporters of my work are those who have had direct contact with orangs: they change lives. The simplest way to ensure their survival would be to get the most powerful people in the world into the forest to meet orangs face to face."

For 23 years she has been involved with building up the biggest ever study of the orang-utan, as well as establishing a refuge to help return captive and injured apes back into the wild. It is not easy work: orangs are solitary, live in trees and have no conformity of behaviour; place 50 individuals in the same circumstance and they will behave in 50 different ways. Jane Goodall once sympathised with Dr Galdikas, saying it would take two years to build up the same depth of study of orangs you could establish in two hours with chimps. So, while Goodall and Fossey were reporting their findings and inspiring books, TV documentaries and movies, Birute Galdikas was chasing specimens across Borneo.

The consequence is that when Orang-utan Foundation - a body that works for the animal's survival - recently did a survey inChester about people's perception of the great apes, almost everyone knew about gorillas and chimps. Knew they lived in Africa, knew they were social and intelligent and in danger. But the only thing most people knew about orang-utans was this: wasn't it an orang-utan that acted Clint Eastwood off the screen in those Clyde movies?

It is to bring attention to the orang's plight that Dr Galdikas has finally, 10 years after the idea was first mooted, been persuaded to stop studying and caring for the apes and write a book - Reflections of Eden (published by Gollancz) - about her experiences. And she has left the base in the rain forest she calls Camp Leakey to promote it.

"The forest is being destroyed by the worldwide economy, by us in the west," she says. "I am not very good at this promotion thing, but it is the best thing I can do at the moment to save the animals. People say to me, what can they do to help save them? I say, come and see me in Borneo. Spend your money there. As soon as people realise there is an economic reason for keeping things as they are, they will."

And, in the meantime, she is taking her message to the people. As I left, she was taking a call from a researcher on Good Morning with Richard and Judy.

"Yes, that's G-a-l-d-i-k-a-s," she was saying. "And it's orang-utans. Orang-utans. That's o-r-a-n-g..."