What is the maximum intellectual capacity of a chimpanzee?

In a fascinating 2003 Atlantic magazine article, James Shreeve documents the case of Oliver, a chimp who normally walked upright, was bald, had freckles, and enjoyed a cup coffee after feeding the dogs. read more

Their chimpanzee "actors" were as interchangeable as the apes in a circus act, being amusing as chimpanzees and not as individuals. Animal rights groups have urged a stop to this practice, considering it animal abuse. read more

Ayumu, a young chimpanzee involved in cognitive research at the Primate Institute of Kyoto University, in Japan, is famously able to memorize the position of the numbers one to nine in random positions on a screen in as little as 0.67 seconds. read more