Scientific attitude has changed towards these relatives of ours, the nonhuman primates. In the 1960s, the strict ethnological science of Europe did not believe that animals had personalities. Only humans had personalities. Animals were presumed to have no ability for rational thought and problem solving. The worst sin of anthropomorphism was that animals be credited with any kind of emotion.
It is fascinating that since 1960, attitudes have softened and there is no longer a passion for reductionism. People are much more prepared to look at the societies of nonhuman animals and see complexity and individuality. Discussing emotions is usually acceptable if it is done in the right way. The animal mind is now a popular study of many graduate students.
The Gombe stream is a 30-square-mile area. It stretches for 10 miles along the shore of Lake Tanganyika, a steep, hilly country, falling down forested slopes from the Rift Escarpment. That area is home to approximately 100 chimpanzees, who have provided us with a wealth of information about primate behavior, including feeding behavior and diet selection, among many others.
The main study community of Gombe consists of some 50 individuals — adults, adolescents, and infants. Male chimpanzees are more overtly aggressive and fight more than females. But because they are ordered in a dominance hierarchy, where males know their positions relative to each other and are dominant to all females, disputes within a community can often be settled by a threatening posture or gesture. A male will bristle his hair, bunch his lips in a ferocious scowl, swagger, brandish sticks and so on.
After some kind of aggression, the victim even though fearful of the more dominant aggressor is likely to approach with some kind of submissive gesture, such as a crouch. In response, the aggressor is likely to reach out with a reassurance behavior such as patting, touching, or even kissing and embracing. And so, social harmony is quickly restored to the group, even after quite serious aggression.
Nonverbal communication patterns of the chimpanzees almost uncannily resemble some human postures and gestures and tend to occur in the same type of context. A nervous female may reach her hand out for reassurance and the male may gently calm her by patting her hand. An adult male may be greeted with a kiss when he joins a young female. Friendly physical contact in chimpanzee society maintains friendships and improves bad relationships. Males will spend long hours peacefully grooming each other, but if two chimpanzees do not like each other, they will not groom. Many of these patterns are inborn; but a young chimpanzee raised in social isolation although he may use these postures and gestures, will do so in inappropriate contexts.
A wild female chimpanzee gives birth approximately every 5 years and usually has her first baby when she is between 11 and 13 years of age. Age of