This book was first written in 1982 and has stayed in print since. It was updated for its 25th Anniversary and this was the version that I read. What makes this book about a group of chimpanzees in a Dutch Zoo so popular with humans?
Chimpanzees are man’s closest ape relatives. We have only 2% difference in our DNA. Chimpanzees are about the same size as humans but are much stronger and have much more developed teeth, especially the adult males, who have canine teeth to rival a panther’s. Chimpanzees are much more acrobatic than humans and make excellent use of both hands and feet. One important difference is that they, and gorillas, cannot swim.
Like humans, they live in social groups that are hierarchically based and that are designed to maximise the well- being of the group and deter potential rivals for territory and food. They can be very aggressive indeed and hunt, kill and even eat other monkeys alive. They can mutilate and kill humans and other chimpanzees and can be highly unpredictable. For this reason humans at the zoo only had direct contact with infant and juvenile chimpanzees.
Interactions between the different individual adult males and females and juvenile chimpanzees were systematically recorded over a period of years. Hierarchy was determined by a development of subservience behaviour in the form of oral greetings and dominant behaviour in the form of displays and assaults. Making up, coalitions, friendly and dominance behaviour were common. In general male adults have the capacity to do more damage but they tend to reign in their aggression, whereas female adults are somewhat less powerful but tend to do a lot more damage in fights.
The leader of the pack, the alpha male, has more opportunity to mate with the females. Males lower in the hierarchy, may or may not be allowed to mate by the alpha male, but sex on the side can be arranged by the support and deceit of a helpful female.
Although the appearance, voice and behaviour patterns of each chimpanzee is individual, it is not usually possible for any male chimpanzee to be sure of the parentage of offspring in the group, since multiple matings often occur. The adult male chimpanzees will curry favour with the females by grooming them and tickling and playing with the babies. Sometimes however, like male lions, and humans, they will kill infant chimpanzees.
What I found fascinating about this book is the way that human behaviour mirrors chimpanzee behaviour so closely. We have better language and tool skills than chimpanzees, and our group activities are much more organised, but every day you will see behaviour that you clearly recognise as parallel to our hairier and not much less aggressive relations.