Jane Goodall greets the audience by imitating a chimpanzee, then launches into an hour-long talk on her relationship with apes and how, from being a primatologist, she became an activist to protect them.

At 78, Goodall, who has 53 years of studying chimps behind her, is still criss-crossing the planet to raise the awareness of populations and their leaders on the fate of the apes and the need to protect the environment.

"I haven't been more than two or three weeks in one place at one time," for the past 25 years, she says.

It all started with a conference on chimpanzees that she attended in the US in the 1980s.

There were sessions on the ethics of chimps being used in medical research, habitat destruction and chimps caught in snares and the beginning of the bush meat trade.

"I went in as a scientist happily learning about chimpanzee behaviour... but I left that conference as an activist," she recounts.

She started her career as an activist in Africa, travelling from country to country with her exhibit -- a collection of photos and some tools used by chimpanzees, who, like all the great apes, are endangered by habitat destruction and the bush meat and pet trades.

"While I was travelling around in Africa, I was not only learning about the need to conserve chimpanzees, gorillas and bonobos, but I was also learning about many of the problems facing African people," she added.

"I was learning more and more about the poverty and the ethnic violence and problems of that sort."

The realisation that many of the problems faced by African populations stemmed from exploitation of natural resources, first in the colonial era and then by multinational companies, led her to realise "it's also clearly important to travel in Europe and North America, and now increasingly in Asia," she told those gathered to listen to her at the National Museum headquarters in Nairobi.

She spoke of the explosion in the planet's human population, of the ever greater need for land, food and housing, and evoked the scarcity of water as well as global warming.

"When I first came to Africa and I flew over Kilimanjaro, even in the height of the summer there was a great cap of snow. The snows of Kilimanjaro," she recalled.

"I just read the other day that we should rather be talking about the dusts of Kilimanjaro. That is just one signal and this is all around the world that the glaciers are melting," she went on.

For Goodall, one of the world's leading chimpanzee experts, "something has gone wrong" in the relationship between man and the planet.

"We've just been stealing, stealing, stealing from our children, and it's shocking. But is it true that there's nothing that can be done? No absolutely not," she goes on, explaining how her latest project, Roots and Shoots, began.

The project, which now spans 132 countries, began in Tanzania, where Goodall, the first scientist to name the animals she was studying -- a practice that sparked controversy, started observing chimpanzees, with just 12 students from nine different high schools.

Roots and Shoots is aimed at sensitising young people to the importance of the environment and fauna.

"Young people are influencing their parents, they are influencing their teachers, they grow up to become teachers and parents, they grow up to go into business, to become politicians," Goodall said.

"I now look back over nearly 53 years of unbroken research in Gombe and I think the thing that strikes me most and probably that has been the most significant in enabling this study to continue is how like us chimpanzees are," she added.

"They are way more like us than we thought back then," she said.

"We didn't know back then the DNA structure of chimps and humans differs by only just over 1%, we didn't know to what extent the immune and blood systems and the anatomy of the brain is similar in humans and chimpanzees and we certainly didn't know how similar our behaviour is," she said, noting that chimpanzees are capable of altruism.

"There is no sharp line dividing us from the chimpanzee or from any of the great apes," Goodall said, whilst also dismissing the idea of a sharp distinction between the great apes and monkeys and other mammals.