Thousands of great apes are killed or trafficked each year in an illegal trade that is driving them toward extinction, according to a joint report from the United Nations and Interpol released last month.

The report, together with statements by conservancy groups, make it clear that the annual multimillion-dollar trade in human's closest relatives was bringing them ever closer to extinction.

While the greatest threat to apes is habitat loss, the illegal trade in great apes, including chimpanzees, bonobos, gorillas and orangutans is taking an increasingly large toll. More than 22,000 great apes were estimated to have been taken between 2005 and 2011, the years covered by the investigation. Many more are likely to have been killed or trafficked illegally.