Tim Radford
Humans have underestimated their closest relatives. They cannot form words, but that does not mean they cannot speak.
Bonobos – pygmy chimpanzees observed in the wild – post directions and leave notes for each other when they disperse on the forest floor.
And recent research has shown something unexpected: a special area of the chimpanzee brain shows exactly the same kind of asymmetry as is found in humans. This is an area called the planum temporale, which is important for language and communication.
Neuroscientists and psychologists are puzzling about the origins of human language, and animal experimenters have been arguing for decades about whether laboratory chimps are really communicating or just learning tricks when they “converse” with humans.
But Sue Savage-Rumbaugh of Georgia State University told a conference in last week that she had no doubt. Using a board with symbols on it, she had asked a chimpanzee to do things that could only be done by a creature that understood symbolic language.
“When apes can understand a sentence like: ‘Go get the tomato that’s in the microwave,’ and there’s a tomato in front of them and they can ignore that tomato and use the modifier ‘that’s in the microwave’ and get that one, that is evidence for an understanding of the language.”
But that did not answer questions about chimpanzee conversations with each other in the wild. She went to Central Africa for two months to answer the question for herself. She found that bonobos were noisy enough in the tree, but once hunting on the ground, they were silent, for fear of predators. She observed that small parties seemed to know where to meet up.
They literally took leaves from nature’s book and used them as signposts and markers for each other.
Chimpanzees and humans share 99% of their DNA: the 1% difference is the blueprint for all the advantage that humans have.
“If you actually take time to look at them and be with them, you understand they are like us,” Savage-Rumbaugh said.