From the dainty use of a leaf as a napkin to saying goodnight with a lip-quivering raspberry splutter, the orang-utan is a cultured ape, able to learn new tricks and pass them to the next generation, researchers say.
The discovery suggests that early primates, which include the ancestors of humans, may have developed the ability to invent new behaviours, such as tool use, as early as 14 million years ago, six million years earlier than once believed.
"If the orang-utans have culture, then it tells us that the capacity to develop culture is very ancient," says Birute Galdikas, co-author of a study appearing this week in Science.
In the march of evolution, "orang-utans separated from our ancestors and from the African apes many millions of years ago," she said, and the study suggests "they may have had culture before they separated".
Culture, in the scientific sense, is the ability to invent behaviours that are adopted by the population group and are passed on to succeeding generations.
Orang-utan culture is crude by human standards, but it is culture nonetheless because it is developed and practised independently by different groups and succeeding generations in the same way that human societies develop and perpetuate unique forms of music, architecture, language, clothing and art.
Ms Galdikas, a researcher at the Orang-utan Foundation International, and eight other international primate scientists analysed years of observations of the South-East Asian orang-utan and concluded the ape can adopt and pass on learned behaviours.
The researchers studied results from observations of six widely separated bands of orangutans in Borneo and Sumatra. Each group had unique behaviours.
The researchers found 24 examples of behaviours that are routinely practised by at least one group and passed on to new generations.
- AP