This is according to a new UN report released on Monday that voiced fears for their survival.
More than 22 000 great apes are estimated to have been lost to the illicit trade between 2005 and 2011, according to the study by the UN Environment Programme, which oversees the Great Apes Survival Partnership (Grasp).
"This trade is thriving and extremely dangerous to the long-term survival of great apes," said Grasp coordinator Doug Cress, describing the illegal trade as "sophisticated, ingenious, well financed, well armed".
"At this rate, apes will disappear very quickly," he said.
Capturing a single chimpanzee alive can require killing 10 others, said Cress.
"You cannot walk into a forest and just take one. You have to fight for it. You have to kill the other chimpanzees in the group," he told reporters on the sidelines of a conference in Bangkok on endangered species.
Sold as pets
The fate of captured gorillas is even more bleak as they die quickly from stress, he added.
International trade in chimpanzees, bonobos and gorillas – the three African species of great apes – as well as orangutans, the only Asian species, is banned under the Convention on International Trade in Endangered Species whose member countries are gathering in the Thai capital this week.
But in reality great apes are sold as exotic pets for wealthy individuals who see them as status symbols, bought by "disreputable zoos" and exploited by the entertainment and tourist industries, the report said.
"Great apes are used to attract tourists to entertainment facilities such as amusement parks and circuses. They are even used in tourist photo sessions on Mediterranean beaches and clumsy boxing matches in Asian safari parks," it said. – AFP