Washington: Scientists have found evidence that chimpanzees living in the wild have pre-existing cultural knowledge.
The study found that neighbouring chimpanzee populations in Uganda use different tools to solve a novel problem- extracting honey trapped within a fallen log.
Kibale Forest chimpanzees use sticks to get at the honey, whereas Budongo Forest chimpanzees rely on leaf sponges-absorbent wedges that they make out of chewed leaves.
"The most reasonable explanation for this difference in tool use was that chimpanzees resorted to pre-existing cultural knowledge in trying to solve the novel task," said Klaus Zuberbehler of the University of St Andrews in Scotland.
"Culture, in other words, helped them in dealing with a novel problem," he said.
"Culture" in this sense refers to a population-specific set of behaviours acquired through social learning, such as imitation, he explained.
This is in contrast to an animal or human learning something on his or her own through trial and error, without taking into account what others around them do, or behaviours that are "hard-wired" and require no learning at all.
Behavioral differences among animal populations have been taken as evidence of culture, the researchers said, but it`s a notion that has remained controversial.
Some think that other explanations-differences in the environment or in genetics-seem more likely.
Perhaps the strongest evidence for animal culture has come from studies on wild chimpanzees in Africa, Zuberbuhler said.
"With our experiment we were able to rule out that the observed differences in chimpanzee tool use behavior are the result of genetic differences because we tested members of the same subspecies," said Zuberbuhler.
They also ruled out habitat influences by exposing the chimps to the same unfamiliar problem.
Zuberbuhler said that they were surprised by how quickly the animals found their respective solutions.
"The cultural differences, in other words, must be deeply entrenched in their minds," he said.
The study was published in Current Biology.