The illicit trade in great apes is robbing an estimated 3,000 primates from the wild each year, according to a United Nations report.
Stolen Apes, produced by the United Nations Environment Program (UNEP) with the Great Apes Survival Partnership (GRASP), estimates that at least 22,218 great apes have disappeared since 2005, with chimpanzees comprising 64 per cent of that number.
Most of the animals are destined for rich collectors, the tourist industry and dubious zoos.
The report was released on Monday at the 16th Convention on International Trade in Endangered Species (CITES), which is being held in Bangkok this week.
All great apes are listed on CITES Appendix I, which prohibits commercial trade in endangered species.
'The taking of great apes from the wild is not new,' said Achim Steiner, UN Under-Secretary-General and UNEP Executive Director.
'But the current scale outlined in this report underlines how important it is that the international community and the organisations responsible for conserving endangered species remain vigilant, keeping a step ahead of those seeking to profit from such illegal activities.'
Since 2007, zoos and private owners in Asia have ordered 130 chimpanzees and 10 gorillas under falsified permits from Guinea alone, the report noted.
'Great apes are extremely important for the health of forests in Africa and Asia, and even the loss of 10 or 20 at a time can have a deep impact on biodiversity,' said Doug Cress, coordinator of GRASP.
The report makes several recommendations for curbing the illicit trade such as establishing an electronic database that includes the numbers, trends and tendencies of the great ape trade.