Study: Chimpanzees have 'culture'

Web posted June 17, 1999

By Joseph B. Verrengia
Associated Press

Some chimpanzees greedily slurp ants off a stick as if it were a wriggling lollipop, while others daintily pluck them, one by one.

Some chimps mop their brows with leaves; others demurely raise their arms while companions groom them.

Researchers now agree that the variety of behavior exhibited by mankind's closest relative can be summed up in a single word: culture.

It is the first time scientists have concluded that a species other than humans has a culture, or a way of life based on customs that are learned and shared rather than genetically programmed.

``The evidence is overwhelming that chimpanzees have a remarkable ability to invent new customs and technologies, and they pass these on socially,'' said primatologist Frans de Waal of Emory University.

The study, conducted by primatologist Andrew Whiten of the University of St. Andrews in Scotland and others, was published Thursday in the journal Nature.

The findings are based on an analysis of chimp data spanning five decades.

Jane Goodall, the world-renowned scientists who has been observing primates at Gombe Stream in Tanzania since 1960 in the longest-running animal behavior project, co-wrote the study.

The research found at least 39 customs related to chimps' tool use, grooming and courtship. The customs vary widely from group to group, much as they do in humans. The scientists said it is too early to tell if some chimp cultures are more advanced than others.

``What we see in wild chimps, on a lesser scale, is the sort of cultural diversity that we would see in traditional human societies,'' said primatologist Craig Stanford of the University of Southern California.

Chimps and ancestral humans split on the evolutionary tree more than 4 million years ago, but the ape's genetic code still overlaps ours by more than 98 percent.

Primatologists generally consider chimps to be as mentally capable as a 4-year-old child, and they share many practices with primitive human cultures, including social bonds, certain hunting habits and the use of plants for medicinal purposes.

Many animal species learn fundamental survival skills from their parents, and their habits differ depending on where they live. Songbirds, for example, learn local dialects of their species' song.

Dolphins swim in groups and have a complex communications system, while elephants display a range of emotions, including grief.

But the extensive types of behavior among chimps are unparalleled and are not necessarily dictated by particular boundaries or environments.

In Tanzania, chimps at Gombe routinely use sticks to probe the ground for termites, but chimps 100 miles away in the Mahale Mountains do not.

Gombe chimps don't use stones to crack nuts, even though their terrain is strewn with rocks. But Tai rainforest chimps in the Ivory Coast use stone tools even though rocks are scarce.

At Tai, grooming chimps wipe parasites on their forearms before mashing them with their forefingers. At Gombe, groomers mash parasites on a leaf.

What remains unresolved is the origins' of chimp customs and precisely how they are shared.

``We're just now beginning to videotape families to see how they acquire these behaviors,'' said Ann Pusey of the University of Minnesota.

The findings raise an important new consideration in the conservation of chimpanzees' rapidly dwindling populations across Africa. Logging, hunting and farming have reduced the chimp population to less than 200,000, down from the millions of chimpanzees 100 years ago.

``We are not just losing chimpanzees,'' Whiten said. ``We are losing the diversity of chimpanzee cultures.''