National Geographic : 1940 Aug
The Manlike Apes of Jungle and Mountain © National Geographic Society Painting by kile Uneverlange Alert White-faced Chimpanzees Pass Intelligence Tests with Flying Colors Many young ones acquire impeccable table manners in the company of humans. Tea and luncheon parties for Chimpanzees have been a London Zoo feature for years. One chimp learned to count up to six. Highly emotional, these African apes are the only primates which habitually express affection by kissing and hugging. Scientists believe chimpanzee intelligence is fully developed between the ages of three to five.