In a series of experiments, researchers in Germany have found that chimpanzees work cooperatively to help each other accomplish a goal.

Brian Hare of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, placed an adult chimpanzee in a cage, in which it was possible to get food by pulling two ropes, the New York Times reported Friday.

In some trials, the ropes were too far apart for one chimpanzee to get the food on its own. Some chimps had access to a door that could allow another chimpanzee to help.

The scientists found that the chimpanzees were much more likely to open the door if the ropes were too far apart and they needed help.

"They know when they need help," Hare said.

The findings are published in Science.

Copyright 2006 by United Press International