Chimpanzees: A friendly gesture
There is a constant interplay between adults in a resting group. New arrivals will greet one another, by offering the back of their outstretched hand to be sniffed and touched with the lips. Elderly males, grey and balding with bright eyes and wrinkled faces, often sit away from the main activity. They may be as much as forty years old and they often give expression of short-tempered irascibility. They are treated with considerable respect, the females rushing up to them smacking their lips and effusively hooting. All of the group, young and old, spend hours grooming one another, carefully sorting through the coarse black hair, scratching the skin with a fingernail to remove a parasite or a scale. So anxious are they to perform this service to one another and so pleasurable do they find it that sometimes a chain of five or six individuals may form, each absorbingly grooming another. It has become a truly social activity and a gesture of friendship.