The communication skills of chimpanzees have also been studied a great deal. They talk in grunts, barks,and other sounds that many people love to imitate. Chimps also communicate with the look on their face on by making gestures with their hands. They embrace and touch each other when they meet. They also spend about an hour a day in a social activity called grooming, where they pick dirt,bugs,and burrs out of each other's hair. They appear to take care of others,knowing that they will also be cared for. They don't seem to fight within the troop,so they must understand each other very well. Scientists haven't been able to teach captive chimps to speak our words,but several have learned sign language for the deaf and can use it very well.