Evidence From Monkeys and Songbirds

Most scientists agree that chimpanzees provide by far the best evidence of animal culture. However, long before this evidence was collected, researchers had reported a possible example of culture in a less advanced primate--monkeys known as macaques that live on Japan's Koshima Island. In 1952, biologists led by Syunzo Kawamura began studying a group of macaques and feeding them sweet potatoes as a way to get close to the macaques for observation.

The sweet potatoes were covered with dirt and sand, which the monkeys routinely rubbed off with their hands. One day, however, a young female named Imo came up with a better idea. She took her dirty potatoes to the water's edge and washed them clean. Within a month, one of Imo's playmates, named Semushi, also began washing potatoes. Three months later, the practice was taken up by Imo's mother, Eba, and a second playmate, Uni. By 1958, potato washing had been adopted by 14 of 15 juveniles in the group and 2 of 11 adults. Even though these monkeys have all since died, the macaques at Koshima Island were still washing potatoes in 2000.

Primates are not the only animals in which scientists have discovered evidence of cultural transmission of behavior. Researchers believe the best nonprimate evidence for culture is found in songbirds, which include thrushes, jays, wrens, warblers, finches, and other common backyard birds. Many studies have indicated that songbirds learn their melodies from parents and neighbors of the same species. Songs within a particular species show regional variations similar to the regional dialects (variant forms of speech) common in human populations. Furthermore, in some bird species, such as the indigo bunting, the nature of songs gradually changes.

Ornithologist (bird expert) Andre Dhondt of Cornell University in Ithaca, New York, notes that the variability of these songs makes them similar to human language, in which new words and new accents appear and change over time. In addition, biologists think of the songs as culture because they represent behaviors that are transmitted through learning and imitation rather than being genetically determined.