There are over 6,000,000,000 humans on this planet. By contrast, there are just 20,000 bonobos, 120,000 chimpanzees and 50,000 gorillas left outside captivity. They are our closest relatives. Incredibly, the few that are still alive are hunted and eaten as "bushmeat", by soldiers and workers of logging companies.

"At the turn of the last century there were some 2 million wild chimpanzees in Africa. When I began my chimpanzee research in 1960, there must have been well over a million. Today... 150,000 chimpanzees remain."

There is nothing new about Africans eating animals killed in the rainforest. What is new is first, the scale of the killing, and second, the fact that it has become a commercial activity. Logging companies, often from Europe, are building new roads, which provide access into deeper areas of the forest. The companies also bring in workers, who often depend on bushmeat for survival. As well as this, the companies' vehicles are used to carry the bushmeat out of the rainforests to markets in the cities.

The bushmeat trade is widely accepted in the region: in Cameroon, everybody from pygmies to the President eats it, and most are unconcerned that the animals are protected and seriously endangered. Although bushmeat trading is illegal, local police are often unwilling to enforce wildlife laws. Forestry guards lack the money or equipment to do the job properly themselves.

A hunter can make as much as $1000 a year from commercial hunting, which is more than the average household income. Hunters typically reinvest their "earnings" in more sophisticated killing technology, which makes the process more profitable and even less sustainable.

The World Bank project to build an oil pipeline through Cameroon will aggravate the problem.?The Bank's Environmental Assessment has recommended that employees of the oil companies should not be allowed to hunt for bushmeat while they are staying in company housing, or working for the company. However, any opening up of the forests will inevitably increase pressure on the animals. Many species are involved, including elephants, forest antelopes, cane rats, pangolins and guinea fowl. However, perhaps the most disturbing is the trade in apes.

Bonobos, or pygmy apes, are our closest living relatives. Genetically, chimpanzees and bonobos are both about 1. 6% different from us; gorillas are about 2. 3% different from us. Gorillas are closer to us than they are to chimpanzees or bonobos. By comparison, the red-eye vireo and the white-eyed vireo, two closely related North American birds, are 2. 9% different genetically.

The best-known bonobo is Kanzi. Kanzi has been on the cover of Time Magazine, and has been involved in language training since 1980. Brought up in a human environment, he is able to understand spoken English sentences at the level of a two year old human, and can communicate simpler sentences by using symbols on a special keyboard.

His utterances show the use of simple syntax, and thus seriously challenge the views of people such as Noam Chomsky, who believe that syntax is a uniquely human phenomenon. Perhaps for this reason, Chomsky refuses to talk to him.

Two of Kanzi's friends, Austin and Sherman, are common chimpanzees. They are able to communicate both with humans and with each other using symbol keyboards. They can recognize themselves on TV, and can easily distinguish between pictures that are recorded and those that are live.

Koko, a gorilla living in Hawaii, can use 500 sign-language words, but understands many times that amount. According to her human trainer, Francine Patterson: "She is learning the letters of the alphabet, and can read some printed words, including her own name. She has achieved scores of between 85 and 95 on the Stanford-Binet Intelligence Test."

Here is an example of a conversation with Koko:

(Koko is looking at a picture of a horse with a bit in his mouth). Koko: Horse sad. Trainer: Why?

Koko: Teeth.

"She demonstrates a clear self-awareness by engaging in self-directed behaviour in front of a mirror... and by her appropriate use of self-directed language... She has produced paintings and drawings which are representational. She remembers and can talk about past events in her life.

"She can talk about what happens when one dies, but she becomes uncomfortable when asked to discuss her own death or the death of her companions."